B'klyn9C1

I thinking of building a LS3/L92 stroker motor to 418 CID to go into a 1995 Caprice. The car is a Daily Driver and I want to produce 500 RWHP/500 RWTQ with good street manners.

I was thinking that since the engine will be apart during the rebuilding process. Is it worth porting (either hand or CNC) the LS3/L92 rectangular port heads or just do a valve and clean up job???

I ask this in light of the fact that Vengeance Racing is able to produce 520 RWHP/500 RWTQ on a 415 CID L92 on Pontiac GTO through a M6 with unported L92 heads and an unported L76 intake through careful cam selection and tuning.

I am particularly interested if just porting the exhaust side will enable me to run a single pattern cam so I can get the most area under the curve and great low and midrange torque, power and throttle response??

Advanced Induction

iTrader: (2)

As is always the case, it depends entirely on the quality and competence of work applied. We've always thought the 30-50rwhp gain was worth the $, but it is on you to judge whether that is a good value for your project. Regarding a partial CNC work setup, we do that, although I don't believe we've put it on the shop/site. For the $ it'll make ~7X% the gain our fully ported head will for ~7X% the $ of the full CNC work. Good luck with your project!

allblowdup

On a 376 ci the heads are pretty good as is but once you get up over 400 ci they really benifit from porting. Cam selection is critcal and porting the xhaust will not change the cam specs needed alot. the big split is from the big intake valve and the factory intake. 500 rwhp would be an easy target to reach with the right cam and the ported heads from pretty much any of the guys on here offering that service.

Sales2@Texas-speed

iTrader: (5)

I voted for ported both intake and exhaust. We've dyno tested the PRC LS3 heads against one of our more popular competitor's exhaust only ported LS3's and the results were very nice! I believe there is still some good power to be had from properly porting the intake side on these heads! The key is in the port/porting!

And I agree, proper cam selection is a must.

Jim85IROC

iTrader: (6)

Your horsepower goals are easily attainable with untouched heads. Whether or not the additional horsepower is worth the cost of having them ported is entirely up to you, but 500RWHP out of a 418 with LS3 heads shouldn't be difficult. There are guys making 500RWHP on stock LS3s with cam/longtubes/tune with Spinmonster's cam.

redsap05

Do not port the heads. All the big gains come from the milling. If you mill the heads most peole get around 20rwhp from just the mill. Same story with ls7 heads.

Advanced Induction

iTrader: (2)

Fortunately, all ported heads are not equal. If X port work doesn't gain, then there is something wrong with it. Same story with the LS7 heads.

Sales2@Texas-speed

iTrader: (5)

Agreed, at this point there are plenty of companies that have ports for both heads that are proven to make power over the stock configuration!

JustAnotherLS2

Agreed. 500rwhp will/should not be difficult.

Jason 98 TA

iTrader: (4)

Made 20rwhp on my 2010 SS with PRC cnc porting & no milling.