350 Horsepower Estimates?

Hey Guys, first post here!

I was hoping to get some HP estimates for my engine, here are the specs. Let me know what you think:

350 .030 over
4 valve relief KB flat top pistons
200cc Dart Iron Eagle heads 64cc chambers (older non-platinum style)
Roller rockers
Comp Cams XE268H
Edelbrock Performer RPM intake
Holley 670 Street Avenger carb
1 5/8 shorty headers

What do you think?

Thanks!


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depending on the compression ratio and profile of the camshaft, i would say an easy 300 hp, conservatively.

~9.8:1 compression

Cam specs:
224 / 230 duration @ 0.050"
.477" / .480" Lift
110 LSA

Desktop dyno puts it at 400hp but I realize that it's a very optimistic program. Just looking for real world input

if zero decked flat tops and 64 cc would be 10 to 1.. you're maybe 9 to 1 to 9.2
I'll say 320hp..

Thanks for the input guys.

The builder said it's around 9.8:1 with the KB hypers. I'm just guessing the iron eagles are 64cc, don't know for sure. Is it because of the valve reliefs you guess it's around 9:1?

no it's because your engine wasn't zero decked.. it's(piston) more than likely down the hole

Ok thanks. It may have been zero decked, not sure. Thanks.

not knowing,, but with those pistons. I doubt it was decked..
blueprinting an engine is costly..
no matter an honest 320 hp isn't bad..
worry about getting the carb and timing dialed in.. many leave tons on the table here..

With the KB flattops, 64cc heads, even with an un-decked block and a .041" thick head gasket you'll be about 9.5:1 CR. The Comp XE 268H cam will give you a dynamic CR of 7.88 with this setup. If you use the GM .028" thick head gasket your static CR will be about 9.8:1, with an 8.15 dynamic CR. With the Fel Pro #1094 .015" thick shim head gasket your static CR will be about 10.1-10.2.

I think you'll have 350+ horse power. The GMPP 350HO Vortec headed engine has a little less CR (9.1:1), heads that flow a little less than your Iron Eagles, and a little less cam (212*/222* on a 112 LSA), so you should be able to put out more than that. The GMPP 350CI 350HP circle track crate engine is the same engine with a GM high rise intake that should be pretty equivalent to your Performer RPM. I think your setup should be able to at least equal this engine.

Please post the piston compression height. If you chose those fosdick reduced compression height pistons (1.540", as compared to the 1.560" compression height of the good guy pistons), SCR could be lower and squish could be wider than what you may think. Throw those shorty headers over the fence and bolt on a set of tuned, long-tube 1 5/8" headers. Tighten the squish up to between 0.035" and 0.045" by jockeying the piston deck height and gasket thickness.

Thanks for the input everyone!

Sorry, I don't have any more details as far as piston height etc. As for longtubes, I've got a 3rd gen Camaro and don't want longtubes due to clearance issues.

Can't wait for spring to come so I can finish up this swap and take her for a spin!!

Techinspector1 makes a good point. Looking at the KB online catalog, all their hypereutectic flattop pistons show a compression height of 1.561", which puts them .001" HIGHER than the nominal 1.56" for a 350 piston. The KB line of "claimer" pistons all show a compression height of 1.565", which is .005" higher than the nominal 1.56". In either case, the CR could be slightly higher or lower, depending on the actual dimensions of your block and rotating parts. Without actual deck height and chamber cc's I just used the "factory spec" numbers.

Ed

BULL HOCKEY!! Fire up the Sawzall and make room. Saying you have clearance issues is almost as bad as saying "my wife won't let me". GET A FREAKIN' GRIP....

after having 3 3rdgens,, headers are a royal p.i.t.a. but totally worth it . for any real gains..

lol

Yes, the stock thirdgen exhaust is a joke, especially the factory Y (or should I say "T") pipe! Ground clearance is poor with longtubes on these cars, not to mention my T5 tranny would be in the way. The hooker shorty headers I have are enough for me and bolt right in.