i have a 302 in my 65 fastback, looking to get it rebuilt and wanted to know how much hp i would have to have at the fly wheel to have around 400 rwhp . would a c4 be ably to handle that? i have 2.80s in my rear end would that handle that kind of hp? willd i have to stiffen the body at all? what reccommendations do you have for the engine rebuild to ge that kind of power?
a few engine and hp questions
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coolblue65
Founding Member
Figure with an auto trans on around 20% power loss to the wheels, so if you want 400 RWHP then you need 500 HP at the block. I dont think its completely impossible out of 302 (unless you want a streetable car) but it will cost you a ton of money. Otherwise, you will need some forced induction and/or stroker motor to pull those kinds of numbers.....
then you probably have and 8" rear end, it will break sooner or later with those kinds of numbers because to put that kind of power to the ground you will need some drag radials/slicks.
Would be fun though
then you probably have and 8" rear end, it will break sooner or later with those kinds of numbers because to put that kind of power to the ground you will need some drag radials/slicks.
Would be fun though
SoCalCruising
Founding Member
400 fwhp = 400 / (1-driveline loss)
= 400 / (1-.2) = 500
as coolblue pointed out.
The strength of your production block is questionable at that power level, at best. Your C4 should get a performacne rebuild, or buy a new one from Art Carr, or others. It will easily handle the power if built right. Your 8" rearend will grenade quite quickly if you have anywhere near that much power. In a naturally asperated 302 that would be streetable, your goal should be about 325 at the wheels. That will require aftermarket heads, cam, intake, carb, & headers, all done right. To get 400 STREETABLE hp, will require a stroker or blower, as said earlier. 325 rwhp is plenty fun in a 65bf.
= 400 / (1-.2) = 500
as coolblue pointed out.
The strength of your production block is questionable at that power level, at best. Your C4 should get a performacne rebuild, or buy a new one from Art Carr, or others. It will easily handle the power if built right. Your 8" rearend will grenade quite quickly if you have anywhere near that much power. In a naturally asperated 302 that would be streetable, your goal should be about 325 at the wheels. That will require aftermarket heads, cam, intake, carb, & headers, all done right. To get 400 STREETABLE hp, will require a stroker or blower, as said earlier. 325 rwhp is plenty fun in a 65bf.
ok so maybe 400 rwhp is out there for me then. if i go more like the 325 rwhp id be looking at almost 400 fwhp. i was looking around and found a 347 stroker kit, what kinda power would i get out of that? ill have someone do the build for me since im not very experienced with engines. would you suggest going with a 9 inch? or just swapping gears out of my 8 in?
ok 1 more question to socalcrusing, what kind of power are you looking to get out of that 331 stroker build? could you let me know when its done id like to hear what it sounds like. because im looking for that low rumble at idle, i hear it a lot in big blocks but yet to her it in a small block. what are you spending in parts on your build???
thanks
ok 1 more question to socalcrusing, what kind of power are you looking to get out of that 331 stroker build? could you let me know when its done id like to hear what it sounds like. because im looking for that low rumble at idle, i hear it a lot in big blocks but yet to her it in a small block. what are you spending in parts on your build???
thanks
ditto, what he said.
I could be done with a monster cam, max bore, 13:1 + comp ratio, allot of head work$$$$$$$$, custom this/that. You'd have to go to the airport for gas or stock your own racing gas. You'd really be pushing it from a 302, not too practicle for street.
The numbers you want can be easily achieved if you bump up to a stroker Windsor, without stressing out the engine.
I have a 408W, 500HP,500TQ on 9.5:1 comp. ratio on 91 octane pump gas.Very streetable.
Quote:"There's no substitute for cubic inches"
good luck
I could be done with a monster cam, max bore, 13:1 + comp ratio, allot of head work$$$$$$$$, custom this/that. You'd have to go to the airport for gas or stock your own racing gas. You'd really be pushing it from a 302, not too practicle for street.
The numbers you want can be easily achieved if you bump up to a stroker Windsor, without stressing out the engine.
I have a 408W, 500HP,500TQ on 9.5:1 comp. ratio on 91 octane pump gas.Very streetable.
Quote:"There's no substitute for cubic inches"
good luck
SoCalCruising
Founding Member
I am looking at about 425fwhp at 5800 RPM with torque peak around 4200-4500 RPM - that is the RPM range that I gave to my cam grinder. I am looking more to maximizing average hp under 6000 RPM than at peak power. 425 will be tough enough to hit at that RPM. Remember that these (even the strokers) are relatively short stroke engines and will suffer in low-RPM power if you get the peaks too high.
There are a number of budget 331 and 347 stroker kits out there to choose from. You can get one for just under $1000 (piston kit, rods, crank and bearings). From there, it's shopping for corresponding parts and getting the machining right. If you are on a strict budget, then you should not ask me how much my motor will cost ... it's too much. Start a new thread asking how to build a budget 347 or 331 and you should get some good input. Guys like D.Hearne have a very good input on how to acquire good parts for not much money.
And, 9" all the way. Gears depend on your power peaks and driving needs.
There are a number of budget 331 and 347 stroker kits out there to choose from. You can get one for just under $1000 (piston kit, rods, crank and bearings). From there, it's shopping for corresponding parts and getting the machining right. If you are on a strict budget, then you should not ask me how much my motor will cost ... it's too much. Start a new thread asking how to build a budget 347 or 331 and you should get some good input. Guys like D.Hearne have a very good input on how to acquire good parts for not much money.
And, 9" all the way. Gears depend on your power peaks and driving needs.
my 302 puts out 325 rwhp/317 rwtq and is relatively simple and streetable, however it probably wouldn't be a good match to your automatic and 2.80 rear gears as to make that kind of power you'll have the rev the motor pretty good (mine peaks at 6500 RPM).
as others have recommended, i'd go for a 331/347 to reach the power you want.
i broke a 9" with my motor, but this was on drag radials and after close to 200 passes at the drag strip (not to mention lots of autocrossing). if you swap to a 9, don't skimp on parts if you're going to drag race on sticky tires.
as others have recommended, i'd go for a 331/347 to reach the power you want.
i broke a 9" with my motor, but this was on drag radials and after close to 200 passes at the drag strip (not to mention lots of autocrossing). if you swap to a 9, don't skimp on parts if you're going to drag race on sticky tires.
