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gflentge 07-10-2012 03:50 PM

engine spec - hp estimate
 
Been reading for a while and see all sorts of posts on HP estimates based on engine spec/build sheet. Been to "ryans" info page and the onfo is great, but there are always unique things .....

Found a 383 already built (someone elses project that they ran out of time/$ For) with following spec and would love to hear opinions on build and estimated hp

Seller says motor was built to make big HP upwards of 480hp and big torque over 500with no spray.... i don't see it, based on the spec hes giving

Any input is great.....good/bad/estimates/opinions...

Specs are.

Intake: Ported Victor Jr.

Carb: Hollwy 750 double-pumper

Heads: Fuelly - 194/150 valves Manley Undercut & Swirl Polished 3 angle valve job ARP Head bolts

Crank: Eagle Cast Steel,3.75" stroke

Rods: Reconditioned GM pinks w/90,000 psi tensil straight bolts

Pistons: Speed Pro Forged and skirted (.125" domed,4.030" over)

Cam: Duration @ 295/305 (roughl) Lift @ .575/.585 w/1.6 hydraullic roller rockers

Rockers: Proform 1.6 full roller rockers

Pushrods: Comp High Tech,stock length

Lifters: Crane,anti pump up

Current Distributor MSD HEI with module and high output coil

Long tube headers

Thanks for input

G

ericnova72 07-10-2012 04:03 PM

My thoughts are... with that valve size and heads not fully ported, he is 100hp too optimistic,... with even the best Super Stock port job at that valve size he is 40-50 hp optimistic.

A set of Dart 215's or similar heads that will flow somewhere close to 250cfm at .550" valve lift on the intake and his guess would then be closer to correct.

gflentge 07-10-2012 05:11 PM

Quote:

Originally Posted by ericnova72 (Post 1572654)
My thoughts are... with that valve size and heads not fully ported, he is 100hp too optimistic,... with even the best Super Stock port job at that valve size he is 40-50 hp optimistic.

A set of Dart 215's or similar heads that will flow somewhere close to 250cfm at .550" valve lift on the intake and his guess would then be closer to correct.

I was estimating around the 400 mark.....

What di you think about a set of ported Sportsman II on same combo....?

Also, that cam seems big....

ericnova72 07-11-2012 11:48 AM

Ported Sportsman II's could be as good as the newer 215's, just depends on how good the port work is.

Cam sound like it is intended to turn up to 7000 rpm. Would be a lot easier to tell rpm range from the .050" duration, and whether it is a solid flat tappet, hydro flat, or roller.

gflentge 07-12-2012 09:29 AM

383
 
Quote:

Originally Posted by ericnova72 (Post 1572919)
Ported Sportsman II's could be as good as the newer 215's, just depends on how good the port work is.

Cam sound like it is intended to turn up to 7000 rpm. Would be a lot easier to tell rpm range from the .050" duration, and whether it is a solid flat tappet, hydro flat, or roller.

Is a hydraulic roller cam.... The seller either doesn't have 0.50" duration or isn't telling.....

And thats why I thought the cam was big....7k with those heads?....sounds like it would run out well below the 7k

ericnova72 07-12-2012 02:57 PM

Quote:

Originally Posted by gflentge (Post 1573160)
Is a hydraulic roller cam.... The seller either doesn't have 0.50" duration or isn't telling.....

And thats why I thought the cam was big....7k with those heads?....sounds like it would run out well below the 7k

I agree... With those heads power is going to go flat at 5500-5800 rpm.

Those heads are just killing what potential the short block has. They would make a good low rpm torque truck motor head, but everything in the 12.5-1 compression short block looks aimed at a 3000-6500+ rpm performance target.


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