....to push a '71 Chevelle 2 door h/t into the 12's?

Oh gads......I don't got's no formulas......
All I can say is this.....Cubes! And Chevy made that easy for us.
454.....or a bit bigger.
There is also a big diff between high 12's and low 12's.
402 will run high 12's with basic mods.....cam, intake, headers, manifold, converter, gears and carb, to low 12's with basically the same stuff on a 454.
My 454 weighed 3900 and ran low 12's, high 11's with ported oval port 215 heads, stock valves, Perf RPM, headers, 3" exh and a TH400 with 3500 stall and 3.55 gears. Cam was a comp Cams 280H retarded 4 degrees. Bottom end torque wasn't an issue.

Have fun! Chevelles are way cool, can go really fast and drive lks a Cadillac on the way home. Mine did.....except for the AC.....
Ron

Well right now I'm running a 350 sbc so that's what I've got to work with at this point.

at least 10-1, good heads, intake, carb and gears, ought to get you close.

Well so far I've got a 4.10 posi, a TH350 tranny with a stock stall, a pair of headers with 1 5/8 primaries and a stock 170 HP firebreathing 350.

I'm looking at crate engines thru Summit. I think I'm going to stay sbc for now so that's why I'm needing to know how much hp/tq it's gonna take. ;)

your current engine and some nitrous :D

Stroke it :D

CAR STATS (http://www.prestage.com/Member+Pages/1201.aspx)

MY VELLE (http://www.chevelles.com/showroom/onebadd66/DSCF0010.JPG)

Nevermind you guys are no help at all....

Originally posted by dirty_dawg:
Nevermind you guys are no help at all.... What do you mean you guys are no help at all??? They were answering your question. You needed to be more specific in asking what you want to know. They say that roughly 400hp can get you into the 12s....but that doesn't mean any car can do that. You have to think about your expenses/budget, car, weight, what you currently have to work with, suspension, tires, etc. There are lots of ways to look at hitting 12s, I mean look at the '69 302ci Z28 Camaro....it ran 12s....then you look at a stock short block 454 with bolt ons, and it'll run 12s, or maybe 11s depending on car and set up. Be more specific, then we can help you out. We're all gear heads here, and love what we do. We're more then willing to help you out...just ask the right questions, and we'll do what we do best, and help you out as best we can graemlins/thumbsup.gif

Ouch Dirty Dawg...you probably shouldn't be insulting people that are trying to help you. If you don't want to know the answer don't ask the question.

it takes an honest 400 hp at the flexplate to get a 3500 lbs car into the 12's with proper gearing and stall/traction too.......about 325 hp to the ground to get you there........but this will just get you in the 12's if your car say is 3900 lbs then you will need closer to 450 hp at the flexplate and about 365 or so hp to the ground.......this should give ya an idea........

roughly every 10 hp you can find will give you right at .10 drop in e.t. and about 1 mile per hour faster..........

thats as long as you are using your horspower efficiently......

to give ya an idea.......i increased my hp by 66 hp on my bbc and that gave me just over 6 mph quicker mph times......thru the 1/4 mile.....but i dont use my horspower effeciently i waste alot of it thru gearing and traction. my bbc makes right about 425 hp at the flexplate and im putting an honest 350 hp to the ground.....but my 3900 lbs car only runs 13.90's at 104 plus mph.....now take that engine and put in a 3500 lbs car with the right convertor and gearing and traction you have very solid mid 12's at even an higher 108 or so mph........

hope this helps........

First off I'm not insulting anyone and I apologize if anyone took it that way. I was very pissed off because I felt a simple question wasn't answered and that people were gawking at my question.

No one up until now said anything about I needed 400 hp to push a Chevelle into the 12's. <--- This was the answer I was looking for. I assume this is 400 RWHP?

All I got was "big block, nitrous, stroke it, have a 10:1 c.r with good heads, intake, etc." Alot of this while I can understand it was not the answer I was looking for. Maybe I should've been more open about it?

Here's my combo....current engine is a bone stock 170 HP 350 LM1. Trans is a bone stock TH350, stock converter. Rear is a 12 bolt posi with 4.10 gears. This combo is what I have to work with.

Stroking the engine is not an option. Modifying the stock bottom end is not an option. Big block is not an option. Refuse to use nitrous. Good flowing heads, matching cam, matching stall converter, matching intake are options.

So basicly what I am planning to do is reuse the stock bottom end LM1 350 but add: better set of flowing heads, deeper oil pan, aluminum dual plane intake, new distributor and better cam with matching stall. Then I will add a shift kit to the TH350.

I think I'm going to keep my operating range between 3000-6000 rpm since the bottom internals are stock.

I've kinda had my eye on the XE274 cam, paired up with a pair of Iron Eagle heads with 64 cc chambers, 2.02/1.60 valves, 200 cc runners and an Edelbrock air gap intake. Of course I've also wondered about the Edelbrock torker II intakes since their power range is 2500-6000 rpm. I will use a 3000 rpm converter with this set up along with my 4.10 posi.

How does this combo sound? Perhaps there's a better combo I'm not aware of?

Yeah man, you had some good answers and the guy who suggest laughing gas was prolly no more than half joking...

Super chevy or car craft or something pulled a 350 from the junkyard and started forcing N2O into it just to see how much it would take before exploding...

Edit: u beat me to it :D
a good set of heads (even factory heads with good casting can be ported decently), decent perf cam, alum intake, 4 barrel carb, headers, efficient ignition, decent air filter, elect. fan, backed by a higher stall converter and some nice gears and you should be well on your way to attempting it

that combo you listed sounds like a pretty good plan but wait for someone with more knowledge than me for a good asnwer

if thats what you got to work with then i will tell you what combo i built for a friend

3.73 posi with 245/60-15 radials
3000 stall with shift kit th350 tranny
750 carb eddy 1407
rpm intake
factory heads that was lightly ported with 1.94/1.50 valves 3 angle valve job
234/244 @ .050 with .488/.510 lift cam
10.2 to 1 compression
summit headers with 2 1/2 " exhaust with turbo mufflers dumped at axle
36 degrees total timming with 91 octane in tank
stock bottom end that was not balanced with 11 to 1 pop up pistons using 76 cc chambered heads....

very first outing with no tunning done in street trim or tach.....13.30's at over 103 plus mph with a best 2.01 60 ft time.....car is 3700 lbs with driver....

this may not be the best choices of parts but it works he drives it everyday it fries the tire under 40 mph rolls really good...smoke and all.......and now thats theres a tach in there it sees 6500 rpms on a regular basis.....

its going back to the track on the 15th with open headers and slicks and do some tunning and i dont see why not this things shouldnt run some high twelves......

another friend of mine just put together a similar combo in his 68 chevelle he just loved how that motor ran he wanted to copy it for his car so i helped him put it together

its alittle different and it has this

4.10 posi
th350 with 3000 stall
bone stock short block with flat tops with 4 eye bow reliefs
59 cc heads steel shim gaskets, heads are 305 h.o. heads that have been highly ported by me with 1.94/ 1.50 valves
same 234/244 cam
compression is just over 10 to 1
torker style high rise intake single plane
750 3310 holley
summit headers dual exhaust

no runs yet but it runs very hard to 6500 rpms and it will be going out on the 15th as well to see how it does......

ddennis is that the XE274 cam that you've listed in your specs? Sounds like a nice combo.

I'm amazed at needing only 400 hp flywheel/325 hp rwp to push this car into the 12's. I'm thinking with my parts mentioned that oughta be easy.

Oh, something else I didn't mention....I haven't had my car weighed yet but it's a sbc/at car with power steering, power drum brakes, no a/c or heater (took 'em out), bucket seats from an early 70's Monte Carlo, no radio, no spare tire, no inner fenders, all steel body panels and still has factory glass, engine is all cast iron.... I'm guessing 3500 lbs.

http://www.race-cars.net/calculators/et_calculator.html

Originally posted by BillK:
http://www.race-cars.net/calculators/et_calculator.html Bill,
That calculator is wrong, it is close to engine HP not RWHP
Below is the basic formula they are using that I have posted before :

""Virtual 2000 among others supposedly gives engine HP I believe.
All I can tell you is to do a few calculations & see if it makes sense to you.
If that calculator was right a 204 mph Pro car woud be making over 1500 rear wheel HP
Assuming a generous 10% loss we are talking almost 1700 engine HP????

Here is a little formula that has been around since at least the 70's & was used by Chrysler Corp. in their drag racing program & written up in the American Journal of Physics in 1973,

HP=(.00426*MPH)cubed * WGT
I add about 50 HP to the number because trap speed is measured differently now than it was in the 70's.

EX:,,,,,,,.00426*97=.41322cubed=.07056*3400=240HP
Add 50 to be nice,,,290HP

I find this formula works pretty fair until you get into some of the very hi end cars like Pro Stock. I find with cars like these it will give you a higher HP number than you usually see, especially adding 50HP.

This formula might be old but I believe most of the laws of physics still apply,,,,,,unless of course you are using that "Good LA air" when you dyno :D :D ""

Mike, I personally believe that Mopar method is pretty accurate for determining flywheel HP. My understanding is that it approximates the power made on that particular run in whatever air conditions were present with whatever accessories and exhaust were used. I think when most folks start talking about flywheel "dyno" #'s they forget that most of those #'s are "corrected" for weather conditions and are not utilizing the same accessories and exhaust systems they would when the motor is in the car.

Just for reference, my car ran 127.2mph@3520lbls and according to the formula this is about 554hp as it sits in the car. Now if I were to put it on and engine dyno and hook up some good dyno headers, lose the alternator and then use a dyno correction factor to adjust for the mid 80dg weather and high humidity it would probably make a "corrected" 625hp or so.

John,
You are correct it will estimate the HP for the prevailing conditions.

One good example is a 496 I did a while back.
Pretty mild deal that made 670HP on my dyno.

This engine made one full pass at Sears point in the evening under very good conditions.
It ran a very "interesting & smokey 10.98 at 132
at which time the gentleman was politely asked to pack it up & not return until adding a few safety upgrades,,, He had a seat belt :D

This is a virtually original 66 SS396 4 speed 3.73 car that weighs about 3500-3600 wet.
I don't remember what tire he had but it obviously wasn't quite enough ;)

Nice deal was it kinda verified my dyno numbers that some have called "conservative",,, I just call them honest.

When did Junkyard Dawg turn into dirty dawg? :confused:

Originally posted by ZZ69chevelle:
When did Junkyard Dawg turn into dirty dawg? :confused: Eh....I originally started as DD a few years ago but only posted once or twice because at the time I was thinking about buying a Chevelle and needed some info....fast foward to a few years later...lost my password and couldn't remember my username so I re-registered. Then one day my computer had some of it's cookies deleted so I told it to resend my password (thinking it would send the JYD password)....and it sent the one I originally started off with.