estimate hp and torque

bad408 · #1 (**permalink**) 12-07-2003, 05:03 PM

just got finished with my new 408w, here are the specs, new motorsports sportsman block machined for 408 cu. in, steel forged crank, eagle h-beam rods, alum pistons yeilding 9.8.1 comp ratio, comp cam hy roller 288-293-236-242-555-576-108, 1.6 rollers, 7qt milodon oil pan, roush 200 heads ported to flow 250@.500 lift and 180 on .ex,263 and 186 @.600 lift, 67.5 chambers, 206 int port c.c. vic jr manifold, bigs 750HP DP, 1\3\4 supercomps, msd billet dist, all balanced and ready to rock, i hope for at least 450 hp and good torque, this motor will be street driven, little strip, cast iron heads for nj weather is a must, or i would have gone with alum heads either AFR 185 or 205's, but i was talked out of using alum heads. thanks.

blykins · #2 (**permalink**) 12-07-2003, 05:55 PM

Desktop Dyno With AFR 185's and your valve sizes says 477hp @ 5500 and 499 lb-ft @4000.

CowtownCobra · #3 (**permalink**) 12-07-2003, 06:21 PM

All those big numbers.... just wait until you get it on a chassis dyno, then reality will set in.

I've got a motor that according to desktop dyno should make 410 hp (at the flywheel, perfect conditions).

Put it on a chassis dyno last week, got 250 hp. These numbers don't mean as much as yall think they do...

Jack21 · #4 (**permalink**) 12-07-2003, 06:28 PM

Don't think you made a bad choice using Roush cast iron heads for street motor durability. But getting talked out of aluminum heads just because of N.J. winters is bad advice. Washington D.C. winters are about the same as N.J. and I'm running TFS aluminum heads.

The major problem with winter driving is salted roads. Anything aluminum will pit from road salt if not kept clean. Aluminum heads do not present much surface area to salt pitting, although the valve covers, and other aluminum components do.

So, you rust belt guys, don't forgo advantages of aluminum heads because of old wives tails. Just keep the engine clean after you drive it.

bad408 · #5 (**permalink**) 12-08-2003, 01:17 PM

thanks for the help, my old 408w made 400 flywheel hp@5900rpm's, 380ft lbs@3000, same block now but i used world sr heads that were poorly ported, they were cnc ported but look like they used a drill bit to do it, also i had a small hy roller lunati 218-228-536-536-112, stealth manifold which i might use again if i lose botton end torque, so i think my new engine guy said i;ll make at least 470 hp on this new combo, my old stroker was chasis dynoed last yr and made 6 runs with tuning, old motor had only 5000 miles or less on it and was not done right from the beginning, mains were showing bad wear, too tight, heads were leaking from valve guides, just a mess but still made 400 hp with all that was wrong, that engine guy was messed up, thanks again.