opinions on summit racing/patriot sbc heads??

[joeelco72]

I'm building a pretty mild 350 i have a brand new gm goodwrench crate motor. im looking to get 450 hp out of it do you think thats feasible with either summit or patriot aluminum heads? i'll be running 9.5:1 w 64cc combustion chambers and Comp xe268 cam w/ 224/230 duration .477/.480 lift, performer rpm intake, holley 3310, 1 3/4" super comps. th350 w/ holeshot 2400 and a 12 bolt with 3.73 and an eaton. do you think i'd have better luck with either of the aluminum heads or the tried and true vortecs?



thanks.

[JEFFTATE]

I don't think you can get 450hp with a 9.5:1 350.
You'll probably get around 360-380 hp with that cam and Patriot heads/ Summit heads.
You may get a little more with some AFR or Dart heads.
But with only 9.5:1 , your not gonna' make that mutch.
( I could be wrong )

[jasonsnova]

yep go afr's and more cam and comp if you want 450hp.... i have a 355 that has afr 195 elimantors air gap intakem lunati voodo 268 cam w/1.6 roller rockers and 9.6 comp, and a bigger 4150 750cfm hp carb and i'm not makin that kind of hp....id say im around 415-425hp , my .02

[JEFFTATE]

You'll get to 450hp a lot easier with a 383cui.

[joeelco72]

hmm...I've seen multiple engine builds using this engine with the results im looking for. chevy hi did a build a couple years back with vortecs with a mild pocket port. Comp XE268H cam and all the basics entailed in my original post. heres a link to Joe Sherman(who won the Engine Masters challenge a couple years ago) and what hes done with the gm goodwrench shortblock. obviously im not Joe Sherman and it seems like he might be running a thinner head gasket or has had the heads milled to achieve the 10.25 to 1 comp. ratio. might be something to check out.


http://www.joeshermanracing.com/CrateEngines.html

[JEFFTATE]

I think the Chevy-Hi builds that achieved 450hp had a little more compression.
You're using a GREAT combination.
And with a little cylinder head work and engine blueprinting , you'll make good power on low-octane fuel.
And have a PERFECT street car engine.
I just don't think you'll get 450hp from a 9.5:1 350cui.

The Joe Sherman Engine had 445hp with 10.25:1.

How can you make 5 more hp with less compression ?
( I apologize , I'm not trying to be a smarta&* , just talking )

[TrickFlowTech]

Exactly which part number GM crate engine are you going to be using as the foundation for this build?

Are you set on using the components that you listed in you original post, or are you open to making some changes?

[joeelco72]

i'm using part #10067353 as the foundation for the build. I am definitely open to suggestions as to the components i will use thats why posted to begin with. The components in my original post are just parts i've seen used with the shortblock that achieve numbers around my goals. I also do not have have gobs of money to throw at the engine I already have a performer rpm intake 7101 hooker supercomps, rebuilt holley 3310, full mallory elec. ignition, I'm just looking to get the most bang for my buck. I'm looking to spend about 1500 on the heads, cam, geardrive, roller rockers etc. so if you have any suggestions that can get me where i want to be with the coin i have to spend they would be greatly appreciated. everybody elses response have been to run afr's. well i know afr makes great heads with great power potential but they also take my whole wife allocated budget. ; )

[cheapthrillz]

A friend of mine just put a set of Patriot heads on his rail motor. Very nice quality! Big block though (like 1100 hp or something ridiculous).

[jasonsnova]

checkout this link lots of combos for the power you are looking for ....gonna be alot easier with good heads tho
http://www.ryanscarpage.50megs.com/combos2.html

[TrickFlowTech]

Reusing your existing components, here's one way (of which there are many) to go:

TFS-30300002 175cc 23* head, 56cc chambers,1.470" springs.
TFS-31400510 1.5 ratio X 3/8" stud full roller rocker
TFS-K31401001 Cam/lifter kit, Flat tappet hydraulic (228*/234*@ .050" dur, .480"/.494" lift, 110* LSA)

Using a Fel-Pro 1094 headgasket (4.100" bore x .015" thick) with the 56cc chamber 175cc 23* heads will bring the compression ratio up to approximately 10.40:1-10.5:1 (Depending on how all of the tolerance's add up...)

Flow sheet for 175cc heads:

Lift: Intake: Exhaust:
100----62-------57
200----127------109
300----180------142
400----219------167
500----242------181
600----245------192

Superflow SF600 bench
Fel-Pro 1204 radius entry
4.030" bore sleeve & head mounting plate
1 3/4" x 4" pipe on exhaust
28" test pressure

This combination should put you into the 400hp/400tq range pretty easily with your existing carburetor, intake & header/exhaust set up. Drivability would be good as well...

Of course, as with anything, there is more than one way to skin a cat. If you do not mind a more aggressive camshaft profile, a single plane intake & higher rpm's, you can make more power, but then drivability will begin to suffer...

I guess the real question is:

What is your definition of a street car?
Do you want the car to have a fairly clean idle? Or do you want a fairly radical idle?
How high do you want to spin the engine?

The problem with trying to get 450hp from this shortblock is that many of the qualities of what make a street car a good street car, will start to diminish as the horsepower levels go up.

Using the above combination on a 10.0:1CR 383 (with the only change being to a set of our 195cc 23* heads) would get you into the 440-450hp / 450tq range pretty easy & the car would have great drivability/street manners....