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Mild 350 vs mild 454?

85K views 52 replies 33 participants last post by  pauls72 
#1 ·
If we were to compare 2 similar chevelles, one with a 350 sbc and the other with a 454 bbc. Both engines would have a mild performance build, at a modest expense, like 750 to 850 dp carbs, aluminum double plain intakes, Iron heads, like vortec on the sbs and oval ports on the bbc, headers, moderate performance cams, around 9 1/2 to 1 compression, auto trannys, similar rear gears. How much better would the 454 perform compared to the 350?
 
#2 ·
454 would wipe up the floor with the 350.....even IF the HP was close(which it won't be) the 350 could never touch the 454's torque....
 
#3 ·
Well it all depends on whos getting traction and who isn't so lets say they both have 500hp and the small block makes 400ft.lbs and big block makes 450-525ft.lbs now take in the fact that the big block weighs about 100lbs more on the front meaning harder to get the hit to the back tires. so If they both dead hook and perform should be a close race. All depends on what you want them to do.
 
#9 ·
Well it all depends on whos getting traction and who isn't so lets say they both have 500hp and the small block makes 400ft.lbs and big block makes 450-525ft.lbs now take in the fact that the big block weighs about 100lbs more on the front meaning harder to get the hit to the back tires. so If they both dead hook and perform should be a close race. All depends on what you want them to do.
harder to get "the hit" to the back tires because of the big block weighing 100 lbs. more? can you explain this by actual experience? I'd really like to understand this....if the big block makes 150 more ft/lbs. of torque than the small block and the both have the same stall convertor,the big block car will flash the convertor to a higher rpm just because of the torque difference.If both cars have lets say,3.42 gears,drag radials and a typical SSM/lift bar style suspension the big block car will 60 ft. harder..without a doubt.
 
#4 ·
both engines if properly tuned, on a mild build, should provide about 1 hp and 1 foot lb of torque PER CUBIC INCH OF DISPLACEMENT
while its true the big block probably will weight about 120 lbs more the difference in power far overcomes the difference in weight

play with this calculator and assume the sbc chevelle weights 120 lbs less than the big block version, but weights a realistic 3700 lbs, and makes 350 fly wheel hp vs the heavier cars 454 flywheel hp and 3820 lbs
now assume both cars loose 20% in drive train losses
http://www.wallaceracing.com/et-hp-mph.php

Your ET / MPH computed from your vehicle weight of 3700 pounds and HP of 280 is 13.77 seconds and MPH of 97.29 MPH.

Your ET / MPH computed from your vehicle weight of 3820 pounds and HP of 363 is 12.76 seconds and MPH of 104.96 MPH.

the calculations may not reflect reality exactly but , they do show the realistic fact that the larger displacement should produce a slightly faster car.
now obviously your going to have someone point out that the big block tends to cost a bit more to build, but its also a good deal harder to make the same power with the lower displacement, given your low budget of only about $700 to -lets say $1000 or so,or so, a good used performance intake, decent flat tappet cam, maybe headers are about all your going to do to either engine
 
#5 ·
HP be damned, you KNOW the 454 will make 100 Ft. Lbs. more torque, all parts being equal.
 
#6 ·
No replacement for displacement. Cubic inches will win every time on similair builds. Even darn near stock the cubes will produce much more torque to easily overcome the weight differance.
 
#7 ·
Z28: 350 V8 360 bhp @ 6000 rpm, 380 lb-ft @ 4000 rpm.
SS396: 402 V8 375 bhp @ 5600 rpm, 415 lb-ft @ 3600 rpm.

I know this isnt what you are looking for, for a comparison but hes saying similar builds. But this is for a camaro ss back in 70 52 cubes more and only 35 more lb-ft and 15hp so that equates to the 100+lbs of weight you are getting right? I am just saying if everything is equal on the road with stock size tires the big block will not hook up as easily as the small block. But what do I know I never had a big block or small block in my nova haha!
 
#8 ·
Last Sunday at our Drag Wars event. A local fellow was there with his 75 Malibu running a 30 over 454, 410 gears, 2200 stall, 28 inch tires, 650 Vac Holley. I forget the cam used. Just under 550 lift, remember that. Running 13.4's. Another BBC TRUD...lol
 
#10 ·
I never got good weight transfer with the 454 in my nova with iron heads. It wouldnt plant as great as the 350. 350 would raise the front 3-4 inches under hard acceleration from a dead stop with minimal tire spin the 454 would maybe raise a 1-2 inches and spin the tires down the road... But what do I know its not my car or anything. and if the front isn't raising its not really putting the weight to the rear end or do you have a car that weight transfers with the front staying down meaning doesn't move at all?

Im not saying im a pro or I am a know it all. But I do know my car pulled harder with a 350 then it did with the 454 either with 3.08s or 3.73s. But hey thats why I am building a 496 aluminum headed solid roller engine.
 
#11 ·
what about 60 ft. Tim? any time slip data to prove your point? Or is this just having fun with a street car (not trying to be sarcastic here)
if your 350 pulled harder than your 454 it must not have been dialed in right

here is a 454 getting some nice "front end raise"..and this was a stock 8 to 1 motor with just cam,headers,intake and 3.07 gears:
 
#12 ·
I use my car on the street. So thats why I said I dont know it all. And my car had 049 milled to 114 cc chambers flat top pistons lunati cam dont remember exact cam specs but was in the neighbor hood of .520ish lift intake and exhaust headers 2.5in exhaust 750 holley and performer rpm and it ran fine but he did not state he was drag racing I was giving him street performance. And that car was on a track with minimal tire spin I run a 275/60R15 radial and the 454 just ate the tires up. So what one is quicker one that is spinning the tires down the road or one that is taking off from a dead stop minimal slip? Had a locker so both tires were spinning. He asked for advice and I was giving it to him. Sorry if you didn't like my info.
 
#13 ·
Being that all is the same BBC will bet the SBC, it's just way to easy to get HP/TQ out of the BB. I hate to say that because I'm a SB guy but it is true.
 
#14 ·
Old crusty saying but..

"No replacement for displacement"
 
#16 ·
When I 'challenged' a buddy's 454 '66 chevelle with my 357 '65 chevelle, I was talking smack to him about how I was going to smoke him off the line because he was driving an overhorsepowered car that he couldn't control.

All just part of my game.

However, I knew that if he got a good start off the line, I was toast.
 
#17 ·
one of the hot rod mags did this same thing with a 72 elky. They put a mild 350 in it and some runs and then pulled it and put a 454 in and did the same test. The 454 won but if I remember right it wasn't by a lot....
 
#18 ·
Static friction. Once that big block breaks the tires loose forget it. It could weigh nothing and the front end still wouldn't come up. That 350 probably had the perfect amount of power/torque to keep the tires hooked. Now if you changed your suspension geometry, gear ratio or tire size and compound to better make use of that big block torque it would have felt like a different animal. Hot rod did a GM crate motor shootout that presented this very issue. Once they started bolting big blocks into thier test mule ( a Chevelle I might add!) the wheelies started to disappear and tire spin started happening. In spite of that, quarter mile times were still quicker. So, even though it's apples to oranges, all else being equal, the big block will produce more h.p. and torque.
 
#33 · (Edited)
(from post #10 by "73 Nova")...

"I never got good weight transfer with the 454 in my nova with iron heads. It wouldnt plant as great as the 350. 350 would raise the front 3-4 inches under hard acceleration from a dead stop with minimal tire spin the 454 would maybe raise a 1-2 inches and spin the tires down the road... But what do I know its not my car or anything. and if the front isn't raising its not really putting the weight to the rear end or do you have a car that weight transfers with the front staying down meaning doesn't move at all?

Im not saying im a pro or I am a know it all. But I do know my car pulled harder with a 350 then it did with the 454 either with 3.08s or 3.73s. But hey thats why I am building a 496 aluminum headed solid roller engine." Tim, read my explanation at the bottom of this post which is below the next quote by Matt....

.... Now if you changed your suspension geometry, gear ratio or tire size and compound to better make use of that big block torque it would have felt like a different animal. .
Matt hits the nail on the head here with this point above^ ....

The following is written for Tim (who wrote post #10 in the first page of this thread), if your car hooked better with the SB engine (all beit on the street which is often a crap shoot anyway) and then that same car you had wouldn't hook (on the street) with the BB engine you installed, it's only due to the fact that with the extra torque of the bigger engine, you then had a rear suspension geometry requirement that was considerably different than that of the SB engine with less torque. NOT because of the extra weight of the BB. :noway:

When we're speaking of suspension "geometry" we're specifically refering to the instant center (or "IC") location. The more power you're attempting to put to the rear wheels with these cars, the greater the need is for a deviation of the factory rear suspension instant center location. The factory suspension upper and lower control arm angles places the IC way out in front of the car, which is much too long of an IC for optimal straight line traction. And that is a known fact. Lift bars, or relocation brackets for the lower control arms are then needed to relocate the IC location. And the shorter IC (shorter meaning that it's closer to the rear of the car than the factory placed it at) will improve straight line traction.

So as far as this comparison, the bottom line is that IF you tend to the IC location requirement of the BB and SB Chevelles which would have all other things being equal other than the weight difference of the two engines in question, the BB car will pull harder out of the hole, and will accelerate better throughout the entire acceleration contest. But again, that's only if you take care of the IC location needs. But if you don't address that inadequecy in the factory rear suspension geometry (more specifically in the factory rear upper and lower control arm mounting point locations) then your big block car will mostly be a tire burnout machine. That's all there is to it.
 
#21 ·
In my younger years I drove and raced street strip small blocks 331 and 355. When I got older and back into cars after kids I bought a Chevelle 4 spd 454 car 280 hyd cam 3.08:1 gearing(that's for you Jim) I then traded and got rid of all of my small block stash. Never going back. That's just how I feel about it.
 
#25 ·
You've all heard about waking a sleeping giant.....stick a cam in a 454 & you will wake it up!
 
#30 ·
Been thinking the same as you TT383. Looking at cost difference's heads etc. Using AFR heads. It looks like upwards $1000 difference between the SBC and BBC. Headers and intake's are very close between the SBC and the BBC. BBC carb is more because of the size needed. Tires,and gearing will need to be different. Extra weight of the BBC vs the SBC. To speak nothing about the demand on the braking system between the two. Plus now you have to worry about braking more drive line parts. Being in my very late 50's I have no interest in lifting a set of heads off a BBC in a car/truck.
 
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