427 without headers, what can I expect?
Thread Starter
Burning Brakes
Joined: Mar 2006
Posts: 927
Likes: 5
From: Bay Area, DubCity Ca
427 without headers, what can I expect?
Here in Ca and was wondering, if I was to have a 427 built for N/A performance, no headers to pass visual, and a cam safe to pass emmisions what RWHP/RWTQ can I expect?
Thank you,
Sam
Thank you,
Sam
Race Director
Joined: Nov 1999
Posts: 12,952
Likes: 0
From: Greer SC
Cruise-In II Veteran
Not quite sure about what you mean by no headers? I think the Lingenfelter 427 pkg is 450 HP & TQ to the rear. On mine (with an A4) I am 500 RWHP & 530 RWTQ and the TQ is a straight-line from 1800-4500 RPM's.
There are so many factors...headers, heads, compression, intake manifold, TB, etc. and most of all the tuning. Keep in mind that peak HP & TQ are not as critical as the total power curve and the reliability of the engine.
Here is a link to the article when Corvette Fever built my C5R-427. We have change several components since then.
http://www.pbase.com/sullyc5er/image/96778010/large
http://www.pbase.com/sullyc5er/image/96778011/large
http://www.pbase.com/sullyc5er/image/96778012/large
http://www.pbase.com/sullyc5er/image/96778013/large
There are so many factors...headers, heads, compression, intake manifold, TB, etc. and most of all the tuning. Keep in mind that peak HP & TQ are not as critical as the total power curve and the reliability of the engine.
Here is a link to the article when Corvette Fever built my C5R-427. We have change several components since then.
http://www.pbase.com/sullyc5er/image/96778010/large
http://www.pbase.com/sullyc5er/image/96778011/large
http://www.pbase.com/sullyc5er/image/96778012/large
http://www.pbase.com/sullyc5er/image/96778013/large
Last edited by Sully C5; May 25, 2008 at 03:18 PM.
Team Owner
Joined: Mar 2005
Posts: 32,275
Likes: 35
From: Somewhere between mild insanity and complete psychosis
Go with some B&B shorties. On a stock displacement ls1 they are worth 10-12 rwhp over the stock manifolds, and they are CARB approved so you'll pass Cali inspection. Stainless Steel, with equal length primaries and really nice collectors. Stay away from the Borla or BBK crap. BBK are mild steel and the Borla are not equal length.
With a proper custom cam grind taking into account the shorties and the need to pass emissions, I still don't see why you couldn't hit 500+ rwhp with all the other little tricks done and some really nice heads.
Yeah you'll have to pay more for less performance than other 427 set-ups, but that's the price for being 100% emissions legal.
With a proper custom cam grind taking into account the shorties and the need to pass emissions, I still don't see why you couldn't hit 500+ rwhp with all the other little tricks done and some really nice heads.
Yeah you'll have to pay more for less performance than other 427 set-ups, but that's the price for being 100% emissions legal.
Le Mans Master
Joined: Aug 2003
Posts: 9,298
Likes: 4
From: American Canyon Lethal Injection
Go with some B&B shorties. On a stock displacement ls1 they are worth 10-12 rwhp over the stock manifolds, and they are CARB approved so you'll pass Cali inspection. Stainless Steel, with equal length primaries and really nice collectors. Stay away from the Borla or BBK crap. BBK are mild steel and the Borla are not equal length.
With a proper custom cam grind taking into account the shorties and the need to pass emissions, I still don't see why you couldn't hit 500+ rwhp with all the other little tricks done and some really nice heads.
Yeah you'll have to pay more for less performance than other 427 set-ups, but that's the price for being 100% emissions legal.
With a proper custom cam grind taking into account the shorties and the need to pass emissions, I still don't see why you couldn't hit 500+ rwhp with all the other little tricks done and some really nice heads.
Yeah you'll have to pay more for less performance than other 427 set-ups, but that's the price for being 100% emissions legal.
Team Owner
Joined: Oct 2004
Posts: 81,241
Likes: 3,063
From: altered state
St. Jude Donor '05
Talk to Caboboy, he has a 421 with a 219 cam, ported SR, AFR heads
. He passes ca smog but not having longtubes will hurt you a bunch.
Id do a smaller motor ie 383/396/406
. He passes ca smog but not having longtubes will hurt you a bunch.
Id do a smaller motor ie 383/396/406
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