BBC vs. SBC : weight vs. power???? [Archive] - Chevelle Tech

: BBC vs. SBC : weight vs. power????


MIKEWITH THE 81'S
Mar 22nd, 07, 7:28 PM
:boxing: That endless battle SB vs. BB.
The age old saying "there is no replacement for displacement". Well I am a firm believer in that, but when you add 200 pounds of weight for 54 cubic inches of engine on the street when is it worth it. We all know that Big Blocks make more torque, but again how much more makes the extra weight worth it.:confused: I have a 406 that i was building for my everyday truck, but I also have a BBC 427 that i was saving for my camaro (yes i know it is a chevelle site. and i am trying to get one of those too):yes:. IS IT TIME TO SAY SCREW IT. Should I put it in the truck I want mid to high 12s and maybe a little bit of the blue bottle. All opinions are welcome.:thumbsup: :beers:

MIKEWITH THE 81'S
Mar 22nd, 07, 7:45 PM
to add a little more......

will some people that drive Big Blocks put your opinions in

kjett
Mar 22nd, 07, 7:52 PM
I think our own John Wilson and Todd Giesler should square off to settle this debate once and for all :thumbsup: Two stout BBC and SBC combos, similar engine displacement and vehicle weight :D My junk will hardly fall out of a tree compared to these guys :sad:

MIKEWITH THE 81'S
Mar 22nd, 07, 8:02 PM
I would like to hear how you got a 396 in to the 10's
also how much power can you make with 049 ovals

furball8994
Mar 22nd, 07, 8:06 PM
Mike. I was always the "small blocks rule" guy. I've had some nasty street SB's in my day.
The first time I test drove my velle (mild 439, untouched 049 heads, 8.5-1 .560/292* solid cam) I became a BB believer.
I can say from experience, "You can't beat a BB. Years ago I had a fairly radical (for a street motor) 406 in a 3200# nova. Its best time was a 11.92@114. The first time I took the velle (3880#) down the track, It went 11.48@116 soft launching. Its gone a best of 11.24@121.
Its been discussed on here before. All things equal, 400sb-v-402bb, The 402 will make more power.

Augustboy2009
Mar 22nd, 07, 8:07 PM
I have had two 396 big blocks and currently run a 496 stroker. To be totally honest, I like small blocks better. I had a 350 rebuilt with stock heads and installed a 327cu/ 350hp cam, and I could rev that thing to 7k no problem. It was nothing special at all! I like RPM's!

furball8994
Mar 22nd, 07, 8:11 PM
I have had two 396 big blocks and currently run a 496 stroker. To be totally honest, I like small blocks better. I had a 350 rebuilt with stock heads and installed a 327cu/ 350hp cam, and I could rev that thing to 7k no problem. It was nothing special at all! I like RPM's!

I like RPM's also. I shift my 439 at 6800 and have a 7200 ship in it.

66 283
Mar 22nd, 07, 8:11 PM
Mike. I was always the "small blocks rule" guy. I've had some nasty street SB's in my day.
The first time I test drove my velle (mild 439, untouched 049 heads, 8.5-1 .560/292* solid cam) I became a BB believer.
I can say from experience, "You can't beat a BB. Years ago I had a fairly radical (for a street motor) 406 in a 3200# nova. Its best time was a 11.92@114. The first time I took the velle (3880#) down the track, It went 11.48@116 soft launching. Its gone a best of 11.24@121.
Its been discussed on here before. All things equal, 400sb-v-402bb, The 402 will make more power.

I am playing both sides of this fence as I have had a few big blocks and over 600 cubes - but i am currently building the ultimate rat killer.

The SBC i am building will have about 428 cubes, heads that flow 440cfm, aluminum block, super light, it could go toe to toe with big blocks 100cubes bigger in the horsepower department naturally aspirated and i expect it to be more reliable (less rotating weight, shorter stroke) than my big block with turbocharger(s).

furball8994
Mar 22nd, 07, 8:17 PM
I am playing both sides of this fence as I have had a few big blocks and over 600 cubes - but i am currently building the ultimate rat killer.

The SBC i am building will have about 428 cubes, heads that flow 440cfm, aluminum block, super light, it could go toe to toe with big blocks 100cubes bigger in the horsepower department naturally aspirated and i expect it to be more reliable (less rotating weight, shorter stroke) than my big block with turbocharger(s).

What stroke are you running to get 428ci? My 439 has a 3.76" stroke. (454 + .060/ 427 crank)
I agree that you can build a killer high horse SB. But I still think (all things equal) a SB can't match a BB's torque.

MIKEWITH THE 81'S
Mar 22nd, 07, 8:19 PM
this will be my first bb experience and i am looking forward to it:hurray:

Twins Fan
Mar 22nd, 07, 8:21 PM
What year is the Camaro? I'm guessing '81 from your screen name, in that case put the 406 in it and the 427 in the truck. If it's a first gen., then put the 427 in the Camaro, I always thought that was an awesome combo, from the whole Yenko thing I guess.

I have a big block, so I say BB all the way.:D A 427 with some juice should get mid 12's no problem. On the street how much time do you really spend above even 5000 rpm, very little. Most of that time is between 2000 and 4000 rpm, that is where a big block shows it's stuff.

67TurboChevelle
Mar 22nd, 07, 8:23 PM
Just add a couple hair dryers to the SB, problem solved, and you get awesome streetability :beers:

Corey

MIKEWITH THE 81'S
Mar 22nd, 07, 8:26 PM
yea my camaro is 81' i was thinking about it but i dont think i need to build the camaro if my daily driving truck is faster??? or do I ........ i think put a big block in the both of them YEEAAAAH!!! sell all but one of my sb400 (2 in shop one at home)

Steve69SS396
Mar 22nd, 07, 8:28 PM
I've got a 460 BB in my El Camino and a 355 SB in my Camaro. The Camaro is faster but the El Camino isn't that far behind plus it is not nearly as radical. My SB Camaro has surprised quite a few BB owners. The new 434 SB should shock the hell out of em! :D

I debated on building a 555 BB or a 434 SB for a while and went with the SB because people expect BB's to be faster.

MIKEWITH THE 81'S
Mar 22nd, 07, 8:29 PM
you know i thought about that when i ran across shortie headers with turbo flanges on them. i was thinking about looking in to that some more. i guess by having the feaver i cannot just plan a simple build. it always grows into a monster beyond reality and pocket book

MIKEWITH THE 81'S
Mar 22nd, 07, 8:31 PM
you know what steve 69 i agree with your statement i know i do.

poor quote but "gas mileage related to hp?"

67TurboChevelle
Mar 22nd, 07, 8:33 PM
you know i thought about that when i ran across shortie headers with turbo flanges on them. i was thinking about looking in to that some more. i guess by having the feaver i cannot just plan a simple build. it always grows into a monster beyond reality and pocket book
I don't think doing a home built system with a blow thru is that crazy on the pocket book. I do know that you giggle like a kid everytime the boost gauge needle leans over :yes:

fabio
Mar 22nd, 07, 8:44 PM
the main advantage of a bb is the heads flow great for stock production pieces. A 11 second big block is somewhat mild compared to a 11 second small block. For these heavy A bodies the torque of a bb is great.

Augustboy2009
Mar 22nd, 07, 8:46 PM
small blocks are cool because you can throttle the burnouts. When I throttle my burnouts with my BBC I always end up redlining it by accident!!! Ouch!

charbilly2001
Mar 22nd, 07, 8:49 PM
Its not simply a weight issue. The BBC heads have always flowed more air than the SBC heads and consequently they make disproportionately more power. For the exact same reason you don't ever see AA/FC or AA/FD BBC's. No matter what the BBC head just won't flow as good as a Hemi.

norvalwilhelm
Mar 22nd, 07, 8:54 PM
I believe in bigger the better. I wouldn't build a 454 anymore. I would go with a 496. It is easy to get 600 horse from one.
That said I went to a small 540, I could have gone 572,598 etc just as cheaply but I wanted to keep it simple.
I then added a 8-71 blower, very good brodix heads and I am hoping for 1000 horse.
I wouldn't build a small block anymore. Not with the 540 so easy to do and 700 horse naturally aspirated so easy to acheive

Silver & Black 69 CAMARO
Mar 22nd, 07, 8:55 PM
To run mid to high 12's you only need the SBC. If this is a summer driven machine and doesn't see much highway usage you can really wake this mouse up. With 406 cubes, a set of 220 or 230 runner Iron Eagles, Victor intake, a hyd. cam about 530 - 540 lift with duration about 225 - 235 max @ .050, --[With the "REQUIRED" matching, springs, locks and retainers]-- a 750 carb, 1-7/8" headers, 10 to 1 comp for pumpgas, 3500 stall and a set of 4.10 gears with slicks, you should look for high or mid 11's depending on the weight of the vehicle. That old half ton would be quite the tiger and would shock the hell out of the local gearheads. ------------- save the "RAT" for the Camaro down the road.

-SS454-
Mar 22nd, 07, 8:56 PM
We all know that Big Blocks make more torque

That is not necessarily true. That old saying came around when big blocks had a lot more displacement on small blocks, but given the same cubes (say 400 ci), the SB can/should make more torque. You can push a lot of air through a SB, but in smaller ports, and that makes loads of torque. BBC heads use very large valves and intake runners, and often larger headers and whatnot, and thats great for big upper end power.

My personal rule for me, is anything under 427 im going SB, anything over, im going big block. 427 itself i could go either way depending on the vehicle.

Silver & Black 69 CAMARO
Mar 22nd, 07, 9:04 PM
I forgot to mention that with the 3.75 stroke you will have a fair amount of torque also. I'm a BBC guy all the way but i would personally build the smallblock as dumping 200 lbs. off the nose sure helps. Now if we were talking a 4.00 inch stroke 454, then go with the larger cubes and stroke as there is no comparison.

Bob West
Mar 22nd, 07, 10:28 PM
I would say there is only 125lbs difference between the engines. A buddy of mine that also runs No/E has a stripped 69 Chevelle, tubbed with 4.86 gears and 32" stickies, 406 on alkiehaul, 15-1 compression,AFR heads,open headers, weighs 1100 lbs less than my car. Now I have him by 100 cubes, but I filled mine with 93 octane on the way to the track and run thru the exhaust. His car is .07 quicker than my car and I run 118+mph in 1000ft while he runs 117+. I'll take the cubes any day :D

66 283
Mar 22nd, 07, 10:36 PM
What stroke are you running to get 428ci? My 439 has a 3.76" stroke. (454 + .060/ 427 crank)
I agree that you can build a killer high horse SB. But I still think (all things equal) a SB can't match a BB's torque.

4" stroke 4.125" bore = 427.65 by my calcs.

66 283
Mar 22nd, 07, 10:39 PM
Its not simply a weight issue. The BBC heads have always flowed more air than the SBC heads and consequently they make disproportionately more power. For the exact same reason you don't ever see AA/FC or AA/FD BBC's. No matter what the BBC head just won't flow as good as a Hemi.

Not always so in the aftermarket. You can buy SBC heads now that rival BBC heads. (mine aren't exactly store-bought but case in point... you need a big chief head to outflow my small block heads.)

ddeennis
Mar 22nd, 07, 10:40 PM
bbc for me, my first taste was back in the early 90's and havent looked back and they are so cheap to build. ;ot of fo;ks think the bbc cost whole lot to build but not to me and im pretty tight with the coin.

i see guys building sbc spending dough on rods, crank and aftermarket heads for sure. then big sloppy cams and end up with issues to drive on the street.

bbc chevy you get to save your dough because the crank rods and heads can go to 10's with right tune no need for high dollaar parts. headers cost the same thru summit compared to sbc, pistons about the same, intakes you can get used for under 100 bucks.

in any case bbc for me. your kinda in class in your own, you dont see to many built bbc in small town USA but you sure can find a crap load of sbc running around...........not winning very much agianst the bbc.........he he he

66 283
Mar 22nd, 07, 10:41 PM
I would say there is only 125lbs difference between the engines. A buddy of mine that also runs No/E has a stripped 69 Chevelle, tubbed with 4.86 gears and 32" stickies, 406 on alkiehaul, 15-1 compression,AFR heads,open headers, weighs 1100 lbs less than my car. Now I have him by 100 cubes, but I filled mine with 93 octane on the way to the track and run thru the exhaust. His car is .07 quicker than my car and I run 118+mph in 1000ft while he runs 117+. I'll take the cubes any day :D

That's true to a point - once you get over 1000hp you can make more reliable hp with a power adder small block than a naturally aspirated big block. Huge cams and triple springs are required. I know, it's an apples and oranges comparison but i think a good small block with a power adder is equally streetable - i have seen the light! There is a lot less weight swinging. I will never build an engine over 600 cubes again unless it is 100% race only.

furball8994
Mar 22nd, 07, 10:45 PM
4" stroke 4.125" bore = 427.65 by my calcs.

Sounds like it'll be a potent Lil stroker. P.S. I'd call it a 427sb. (428 sounds like a f#@d motor) The new LS7 427 is a 4.125 bore and 4.00 stroke.

pdq67
Mar 22nd, 07, 11:04 PM
I've had through the years;

A 262 Monza, a '55, 265, two 283's, my old junk301, a hopped up 300hp/327, my -151 cammed L-48 350SS engine, my hopped up 406SB, a hopped up 11.5 to 1 Cr., solid cammed, 409 "W" engine and now my 496BB.

As for ALL of them, the "grin" factor has to go to my old junk301!!!

pdq67

66 283
Mar 23rd, 07, 1:31 AM
Sounds like it'll be a potent Lil stroker. P.S. I'd call it a 427sb. (428 sounds like a f#@d motor) The new LS7 427 is a 4.125 bore and 4.00 stroke.

Gotcha but at this point the heads don't look like chevy or anything else ever produced in a factory for that matter either so the cubes are not relevant anymore LOL. I won't call it anything LOL except for stock if it fits under the flat hood.

Shawn Gilbert
Mar 23rd, 07, 4:19 AM
Not always so in the aftermarket. You can buy SBC heads now that rival BBC heads. (mine aren't exactly store-bought but case in point... you need a big chief head to outflow my small block heads.)

Sure if you purchase 14-18 degree heads and compare then with relatively mild IN COMPARISON 23 degree BBC heads. If you go as far away from a stock configuration and spend as much time and money porting the BBC head to be comparable then it will out flow the SBC head.

You however make a good point. Each has their own merits and can work equally well depending on expectation and use. If you want low compression durable Naturally aspirated HP on pure pump gas well we all know its BBC.

Now if you going to run power adders that increase HP to the point you eclipse your traction threshold ( like 90% of the turbo or procharged cars ) then SBC might be the way to go as it's power characteristics might be some what easier to harness on small tire cars. IE like 10.5 outlaw and SS 10.5 ect. I mean if you are making 1800 HP with a SBC and cant hook up anything past 1200 what difference does the motor really make in the argument, You will probably be better off without the extra 150lbs on the nose in this scenario as well.

However just from an argument and physics stand point if you need to make the maximum amount of power possible of coarse its always going to be the larger displacement engine with everything else balanced out in the combo equally. Notice i did not say with the same parts.

In other words you will never get a 434 to make more power than a 632 with equally matched components OF THE SAME LEVEL OF Radicalness. Meaning not the same size cam as the small block, but instead a cam of equal size relative to the larger engine providing the same effective RPM range and characteristics. Or comparing completely custom 440 CFM go to hell SBC heads with custom intake entry angles and exhaust spacing requiring custom headers and intake components to off the shelf readily available to be shipped to your house overnight 23 degree heads sporting 420 CFM that will bolt right up using average everyday components. I could go on for ever here Compression, cylinder wall thickness, ability to absorb large amounts of N20 blah blah.

If you stay true to the spirit of each engine build there is no way a naturally aspirated SBC can hang with a similarly built big inch BBC. I further state that depending on power level expectation that somewhere around 600 ish HP it becomes more economically feasible to build a durable BBC.

SBC's definitely have their place ( even in my own heart ) and work better in certain situations than their big brothers, but at the end of the day TOP fuel isnt going with the less is more approach in the cubic inch department ;)


Just my 2 on it......oh did i mention they are more cosmetically appealing as well :cool:

Shawn

senior
Mar 23rd, 07, 8:37 AM
:yes: I agree Dominate67. :hurray:

Besides of you guys that run around in a 12-15 sec street cars, just how many can really notice the performance diff if you have a passenger or not??
Some complain about a 200lb motor disadvantage then put it in a larger car anyway :cool:

They both have there place but "there's no replacement for displacement"

:beers:

MIKEWITH THE 81'S
Mar 23rd, 07, 2:24 PM
:thumbsup: thanks for info on 049. does anyone have any other info on these heads. i found a flow chart for them i think in chevy hi performance, but i want to know with a little porting how much power and torque can i make. I would think it should be waay easier to make like some huuuge torque numbers on the street like 550-600ft/lbs. and still get somewhere in the neighborhood of 500hp. Once again I ask "am i asking for too much. I am thinking about the 427 route just because the pistons i already have are such of that, but i have no crank. i really only need power up to 5500 rpm.

MIKEWITH THE 81'S
Mar 23rd, 07, 2:36 PM
:yes: I will not be racing but maybe once a month, but i enjoy shredding tires!!! :eek: :ee

Forget #'s if i could knock down low 12's consistantly wtih the 049s (which i already own) then i will build the big bloc for the truck. :yes:

71454Chevelle
Mar 23rd, 07, 2:37 PM
:thumbsup: thanks for info on 049. does anyone have any other info on these heads. i found a flow chart for them i think in chevy hi performance, but i want to know with a little porting how much power and torque can i make. I would think it should be waay easier to make like some huuuge torque numbers on the street like 550-600ft/lbs. and still get somewhere in the neighborhood of 500hp. Once again I ask "am i asking for too much. I am thinking about the 427 route just because the pistons i already have are such of that, but i have no crank. i really only need power up to 5500 rpm.

Last year I had my heads off to change valve springs & check a few things. While I had them off the motor, thought it would be a good time to have them put on a flow bench and have them checked.

My home ported 049 oval ports had bowl blending, intake gasket matched and smoothed out the exhaust ports abit. They have 2.19" intake and 1.88" exhaust valves installed with no chamber work. I did all the porting myself.

I had Mike Stark from Creative Flow Management (CFM) here in Indianapolis
flow the heads.

http://www.cfmperformance.com/cfmhome.htm

Valve Lift Intake CFM Exh CFM % Exh to Intake
.100 85 69 81%
.200 142 115 81%
.300 210 140 67%
.400 266 168 63%
.500 301 180 60%
.600 308 192 62%
.700 307 196 64%

Average intake to exhaust flow: 68%
Radius entrance on intake port. No pipe was used on the exhaust port.

All in all I was pretty happy with the results. Mike said the exhaust side was down a little compared to what he normally sees on BBC exhaust ports. The reason for this is that when I ported the exhaust side I missed a couple of small things that he said is hurting flow a little. He told me it would be very simple to correct with a die grinder and a little time (which I did before I reinstalled the heads). Mike said with these modifications the exhaust flow should pickup 15-20 cfm. He told me my heads will flow enough air to support 600 + horsepower.

Harold Sutton
Mar 23rd, 07, 4:41 PM
Furball, That Ford 428" motor is really 426.5" (4.13 x 3.98) only those 426 and 427 designations were already being used by Chrysler and G.M.

Twins Fan
Mar 23rd, 07, 9:39 PM
I am thinking about the 427 route just because the pistons i already have are such of that, but i have no crank. i really only need power up to 5500 rpm.

No crank, you didn't say that before. Stroke that thing to a 489 - 496 depending on bore size, and the power numbers you're looking for will be there without even trying.:thumbsup:

Junkyard Dawg
Mar 23rd, 07, 9:58 PM
Well you are running an 81 Camaro which is a bit on the heavy side unless you've gutted it....so naturally you need torque, though it's a toss up on this one....

Might be better to run the 406 in your Camaro, at least then you can go to the counter at Idiot Zone/Retard Auto/Poop Boys and not have to play 20 questions with the clerks when you tell them "it's for an 81 Camaro with a 350".....try that with any big block....

Then later when you can afford it step up to a 496 and let the real fun begin.

1bad69+70camaro
Mar 23rd, 07, 10:07 PM
i have wondered this also. big or small, ask a woman!

MIKEWITH THE 81'S
Mar 24th, 07, 2:06 PM
Every one has given a lot of info, but I would like to take a poll to do that i think i will have to start a new blog. so stay tuned to that same bat channel!

BillyGman
Mar 24th, 07, 3:04 PM
I usually avoid BB vs. SB debates concerning both engines having equal displacement, because my main motive for choosing BB engines is that you can squeeze more displacement out of them w/a stroker combo, and that to me is the real advantage. And as far as I'm concerned, there's just no debating that more displacement will mean more power with all else being equal. It's a physical law that cannot be changed (again, with all else being equal).

66 283
Mar 24th, 07, 4:05 PM
Sure if you purchase 14-18 degree heads and compare then with relatively mild IN COMPARISON 23 degree BBC heads. If you go as far away from a stock configuration and spend as much time and money porting the BBC head to be comparable then it will out flow the SBC head.

You however make a good point. Each has their own merits and can work equally well depending on expectation and use. If you want low compression durable Naturally aspirated HP on pure pump gas well we all know its BBC.

Now if you going to run power adders that increase HP to the point you eclipse your traction threshold ( like 90% of the turbo or procharged cars ) then SBC might be the way to go as it's power characteristics might be some what easier to harness on small tire cars. IE like 10.5 outlaw and SS 10.5 ect. I mean if you are making 1800 HP with a SBC and cant hook up anything past 1200 what difference does the motor really make in the argument, You will probably be better off without the extra 150lbs on the nose in this scenario as well.

However just from an argument and physics stand point if you need to make the maximum amount of power possible of coarse its always going to be the larger displacement engine with everything else balanced out in the combo equally. Notice i did not say with the same parts.

In other words you will never get a 434 to make more power than a 632 with equally matched components OF THE SAME LEVEL OF Radicalness. Meaning not the same size cam as the small block, but instead a cam of equal size relative to the larger engine providing the same effective RPM range and characteristics. Or comparing completely custom 440 CFM go to hell SBC heads with custom intake entry angles and exhaust spacing requiring custom headers and intake components to off the shelf readily available to be shipped to your house overnight 23 degree heads sporting 420 CFM that will bolt right up using average everyday components. I could go on for ever here Compression, cylinder wall thickness, ability to absorb large amounts of N20 blah blah.

If you stay true to the spirit of each engine build there is no way a naturally aspirated SBC can hang with a similarly built big inch BBC. I further state that depending on power level expectation that somewhere around 600 ish HP it becomes more economically feasible to build a durable BBC.

SBC's definitely have their place ( even in my own heart ) and work better in certain situations than their big brothers, but at the end of the day TOP fuel isnt going with the less is more approach in the cubic inch department ;)


Just my 2 on it......oh did i mention they are more cosmetically appealing as well :cool:

Shawn

Shawn, it's great you can estimate my traction over the internet - maybe you can email me my timeslips too? LOL LOL

And the rules in the racing classes do not put a number on your "radicalness" as you put it HA HA HA!! If you judge this magic "radicalness" by durability and driveability, my small block will hands down beat my 632. No need for .900" lift cams and 350/1000lb valvesprings... what i'm saying is that with turbochargers cubic inches mean less and less....

pdq67
Mar 24th, 07, 5:27 PM
Only cubic money beats cubic inches and that's where the TT's come in!!

Just look up the spec's of the 917-30 Porsche race car that ultimately got outlawed b/c it kicked too many Mclaren 495" and 510"s..

That OR compression, rpm and oxygenated FUEL like a wood alcohol and nitromethane mix......

pdq67

67TurboChevelle
Mar 24th, 07, 9:28 PM
hmmmm I built my TT setup for $3000, that doesn't seem like that much cubic $$ to me.

I know the streetability is much better compared to a NA motor trying to make the same power :yes: and I haven't even leaned on it yet.

1969ss396
Mar 24th, 07, 11:11 PM
I chose the big block. I enjoy the brute torque, and the deeper tone of a big block.

A few years ago, Hot Rod ran an article entitled big block vs. small block where they took 2 408's, big block and small block, and compared the 2.
They ran iron heads, the same compression, similar cam profiles, and I think the same carb. The big block made more power and torque on the dyno. And they put the engines in a camaro and ran down the track. They did not change anything in the car, except the engines. Once again, the big block won.

We all have our own opinions on the matter, and I guess it just boils down to what you like and how much money you have. I personally feel the big block has the advantage due to better designed cylinder heads.

I live in an area where everyone thinks that a 350 is made of magic, and nothing is better. I just got so tired of hearing about it, and around that time a buddy took me for a ride in his nasty 455 olds. It did not take me long to make my choice.

You can put twin turbos on a 434 small block and make over 1,000 hp on pump gas all day long, but just think about this--if you have that type of money why not make more power with a turbo 502?

My wife's name is Sally. I told her when we were dating the song "Mustang Sally" had been renamed to "Big Block Chevy Sally."

I am BIG BLOCK for life.

BillyGman
Mar 24th, 07, 11:13 PM
Well, this thread seems like it's taking a turn from SB vs. BB, to N/A vs. forced induction, so let me add that after driving a car that had forced induction (namely a supercharger) for 3 years on a daily basis on the street, here are my thoughts from that experience....

....the plus side of forced induction is the stealth factor. As it's already been indicated, you can put together a more street able engine w/a means of forced induction. I say more street able, because it will eat less gasoline the majority of the time when you're in traffic and just cruising than a bigger Naturally aspirated engine will, and with any means of forced induction, you don't need to reach for the radical cam profiles to make some big power.

However, the one thing that's the deadly enemy of forced induction, and one that it's more prone to than naturally aspirated engines, is detonation (ie. pinging, knocking). Now all the experts will tell you that it's all in the engine tune, and that if the forced induction engine in question is tuned properly with the appropriate ignition timing and air/fuel ratio, then you can avoid detonation. And inter coolers go a long way to help avoid detonation too (at least with superchargers). But there are those who claim that it's one thing to stay away from the engine pinging that can be heard with the ear, but it's another thing to also avoid the pinging that you won't necessarily always hear with the ear. Particularly if you have a loud exhaust system.

Some people use electronic knock sensors, that are hooked into timing retard set-ups. But some people don't use that. But I know of plenty of guys who ran a means of forced induction who also had knock sensors,(I'm one of them) and a number of them still destroyed engines which exhibited signs of engine knock when they were taken apart.

Signs such as broken spark plugs, blown head gaskets, and cracked pistons. Which are all tell tale sings of engine knock. And I'm talking about engines that only had from 20,000-30,000 miles on them. However, in many of those cases, there wasn't any engine knocking that was audible to the drivers' ears.

My point is, that forced induction has it's plus side, as well as it's down side. After my experience with forced induction, I was left with the impression that because of forced induced engines tendencies to detonate ( even with a conservative engine tune) I think that a bigger, naturally aspirated engine is more prone to better longevity, since it won't be as prone to knocking/pinging. And I'm speaking specifically about cars that are street driven often.

Whether or not anyone agrees with me on that viewpoint doesn't necessarily matter, but I believe that the bottom line is that nobody can rightfully claim that any means of forced induction is superior to natural aspiration. Because there are pros and cons with each. This hobby is all about trade-offs, and with most aspects of it, you simply can't have it all. If you reach for one thing, something in another area of your vehicle will have to take a back seat. So it's up to each individual to decide what's best for him and for his specific application. There is never just one way that is best overall for everyone. It depends on what your priorities are, as well as on what your intended useage for your vehicle is.

cuisinartvette
Feb 3rd, 11, 10:45 AM
Anyone know the approximate weight difference between


BBC with alum heads/intake

SBC with alum heads/intake


Love a radical sbc but after the high cost and a premature breakage Im giving serious though to going BBC. Guess once its running again if Im not satisfied its getting sold and be building a Rat. Too expensive to get a SBC to really hum if youre using good parts...guessing a ported alum head, nice solid FT on a BBC should do the trick without getting too out of hand $$ wise.

Dont like the added weight but to stroke mine for another 30-40 ci and 40-?? lbs torque just isnt going to do it and not worth the $.

69chevellesupersport
Feb 3rd, 11, 5:04 PM
IMO build whatever best suits your application. No engine is always the right choice but I would not let other peoples opinions decide what you build.

As far as the big block vs small block I give credit and respect to any well built engine. What I don't like is when certain small block owners boast about beating a NA big block then turn around and complain how they need a power adder to win when they lose to one. Oh and if a big block has a power adder they go crazy! If ya got a small penis either use what you got and shut up or get it enlarged. Lol