ok guys i know none of you like taking guesses at engine hp but im going to throw this out there anyway because i dont have the slightest clue how mutch my engine would be making off the fly wheel and im probably never going to get a dyno test anytime in the near future. so heres what i got, 1971 302 that is bored 30,000 over, it has forged flat to pistons, a high energy can from comp cams high energy push rods, edelbrock dual plane performer intakemanifold, HEI distributer, stock rebuilt heads from 1971 and of course hooker headers
Cam StyleHydraulic flat tappetBasic Operating RPM Range1,300-5,600Intake Duration at 050 inch Lift218Exhaust Duration at 050 inch Lift224Duration at 050 inch Lift218 int./224 exh.Advertised Intake Duration262Advertised Exhaust Duration270Advertised Duration262 int./270 exh.Intake Valve Lift with Factory Rocker Arm Ratio0.493 in.Exhaust Valve Lift with Factory Rocker Arm Ratio0.500 in.Valve Lift with Factory Rocker Arm Ratio0.493 int./0.500 exh. lift i think the compretion is around 10.0:0
with that cam and compression I would guess closer to 275 or so at the wheels. As long as everything else is up to par. I would port the heads if I was you though. Maybe even upgrade to the 1.90/1.60 valves.
a few years back I built a 302 with 10.5 compression, had a .471 lift 276/286 duration cam with a perfomer RPM intake, 750 vac sec. carb, full length headers, crane Hi-6 ignition on stock heads and made 320 hp to the wheels at 6800 rpm. The engine I am building now I hope to take to a dyno soon.
ya i also forgot to say that i have a 600cfm 4b holley carb and i think the only thing that the machine shop ended up doing to my heads was clean them up and put heavy springs in
I strongly disagree with the 275 at the wheels. That's alot of power with only a very mild combo. We're not even talking Performer RPM, just a regular Performer. 275 at the wheels is roughly 345 at the flywheel! Well over 1 hp per cube. I ran the combo through the engine analyzer and come out with 237 FWHP @ 4500 RPM, with 94% VE... or 190 RWHP through a C4 and stock driveshaft. It was quick for me to do since my 72 had the same parts except for the 700 Holley! So I cheated a bit. I just had to swap carbs. The program I have has been almost dead on when compared against known results for several engines I have plugged in for friends. Scary close! So I trust it pretty good. Also, having had the same combo in a Maverick, the 190 RWHP 'felt' right.
What program are you using? Keep in mind I also said " if everything is up to par" he could make that much. I didnt know a 600cfm carb was going to be used. And with the cam that is in use that cam is good for 350hp. That is why I posted my little example of how much power I got out of a 302 with a smaller cam. Everything has to have balance in order to make the power. I mean you cant ignite a ton of fuel on a stock ingnition. with a 600cfm carb, performer intake, and stock ignition you are right he would probably be in the 190-200hp range. Also, how is the exhaust setup and what size pipe?
Hey Seth just for a FYI and to make it easier 30 thou is actually written .03 machinists have it all backwards. One hundred thou is written .1 one hundred and fifty thou is written .15 for the rest of the world .1 is a tenth .01 is a hundreths .001 is a thousandth. The easiest way to explain it is this(and the way I tell all of our new employees) the US machining standard is based on millionths of an inch so when you see .03 or thirty thou what you are actually seeing is thirty thousand millionths of an inch or .030000 with an inch being 1 million and the baseline being .000001 (please dont take this the wrong way I am trying to help and make it easier for you to understand, and easier to write ):16suspect
The biggest limiting factors are the intake and heads. Most analyzers don't even take ignition into count. They just assume you have the best possible version for your combo, which would probably just be DS2 in this case. I have Desktop Dyno and Performance Trends. I only use the Performance Trends though. It comes up with much more realistic numbers and gives you more detailed data in the end. It also offers tech suggestions to improve your combo. The only thing I don't like about that is they are in very technical terms, so you have to think it through very well to tweak your combo with their suggestions.
