Easiest Mod For 10 Extra HP??
Le Mans Master
Joined: Mar 2002
Posts: 7,456
Likes: 2
From: Coming home from Luckenbach Texas
Originally Posted by Eddie 70
Why not change the cam right out of the box? That will put you over the 300 Hp mark.
But a decent set of Vortec (or similar) cylinder heads would really wake that engine up!
Le Mans Master
Joined: Jun 2002
Posts: 8,339
Likes: 24
From: I can walk to MA
Just say
"It 'only' has 290 HP, but I was looking for good torque."
Don't say 300, or the TSP will all be calling you Lying Les.
A shim-type head gasket might push the compression enough to get you 10 ponies.
"It 'only' has 290 HP, but I was looking for good torque."
Don't say 300, or the TSP will all be calling you Lying Les.
A shim-type head gasket might push the compression enough to get you 10 ponies.
Burning Brakes
Joined: Sep 2004
Posts: 917
Likes: 0
From: Vernon British Columbia
St. Jude Donor '05
First C3 General Poster!
Yea running a relly tight quench around .027" might help a little... so far all of the advice has been spot on, the carb spacer, KnN filter, Royal Purple all around, and electric fans, that right there will free up at least 10, probably a lot more.
Le Mans Master
Joined: Mar 2002
Posts: 7,456
Likes: 2
From: Coming home from Luckenbach Texas
If he does a fancy cam, he might as well get the plain LM1. That's about the only thing different between the two. And the savings would buy a cam...and at least 1 head!
Race Director
Joined: Feb 1999
Posts: 19,659
Likes: 34
From: Lenoir City Tennessee
Ci 6, 8 & 10 Veteran
St. Jude Donor '05-'06-'07-'08-'09-'10-'11-'12-'13-'14-'15
Les, when I dynoed mine I only had 253 RWHP and 300 FT LBS. I would love to have 300 RWHP one of these days. I was a little disappointed but I am more than happy with the performance. I have since done some tuning on the carb and timing and it feels stronger than it did when it was dynoed.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Thread Starter
Race Director
Joined: May 2003
Posts: 11,814
Likes: 9
From: Science Bitch! Mississauga, Ontario
Canadian Events Coordinator
Melting Slicks
Joined: Apr 1999
Posts: 2,010
Likes: 3
From: Moon Twp. PA USA
Originally Posted by 81 Vette
Yea running a relly tight quench around .027" might help a little... so far all of the advice has been spot on, the carb spacer, KnN filter, Royal Purple all around, and electric fans, that right there will free up at least 10, probably a lot more.
Thanks,
Burning Brakes
Joined: Sep 2004
Posts: 917
Likes: 0
From: Vernon British Columbia
St. Jude Donor '05
First C3 General Poster!
That really all depends, running a running a tight quench wont create any major problems depending on what your piston-to-wall clearance is, the smaller and tighter the piston is, the tighter the quench you can attain. Also, Depending on where your deck height on the piston is, negetive and to what extent, that has a lot to do with determining the thickness of gasket you can use. Say it was a negetive .005 deck height piston, with a .027 cometic gasket, youre looking at overall .033, which is VERY tight true, but if this is a hipo engine using high very quality parts and tight wall clearences, you should be ok. Now if this is a slightly more run of the mill sort of engine where clearences havent been checked to be that tight, then I would say moving up to a .030 or .036 might be more advisable. A lot, if not most hipo engines use a final clearence of around .040 after deck height is factored in, Ligenfelter engines run a .037 after deck height.
Team Owner
Joined: Jul 2004
Posts: 40,404
Likes: 791
From: Redondo Beach, California
If 290 HP is the engine power that GM expects this engine to produce on a dynomometer then you won't be able to get any extra horsepower unless you modify the basic engine configuration.
For example, lets say you buy an Edelbrock Performer crate engine. I saw one running on the Edelbrock dyno. I think they dyno run all of their engines before delivery. The engine I observed was a 350 cubic inch engine. It had headers installed and the engine was driving its water pump. The carburetor being used was the one the engine was to be delivered with. It produced 412 HP at an rpm just a little over 6000. Obviously, if you receive this engine you won't get any extra HP unless you modify something about the engine.
...so what I'm saying is that if GM rates their engine HP similar to Edelbrock, you can't get any extra HP unless you modify the engine.
PS. That Edelbrock engine really had an awesome sound, even at any rpm. I wish I had know more about the Edelbrock crate engine quality before I bought my GM ZZ4.
For example, lets say you buy an Edelbrock Performer crate engine. I saw one running on the Edelbrock dyno. I think they dyno run all of their engines before delivery. The engine I observed was a 350 cubic inch engine. It had headers installed and the engine was driving its water pump. The carburetor being used was the one the engine was to be delivered with. It produced 412 HP at an rpm just a little over 6000. Obviously, if you receive this engine you won't get any extra HP unless you modify something about the engine.
...so what I'm saying is that if GM rates their engine HP similar to Edelbrock, you can't get any extra HP unless you modify the engine.
PS. That Edelbrock engine really had an awesome sound, even at any rpm. I wish I had know more about the Edelbrock crate engine quality before I bought my GM ZZ4.
Melting Slicks
Joined: Jan 2004
Posts: 2,527
Likes: 1
From: St. Petersburg, Fl///Columbus, Ohio
Originally Posted by AGVI
I'm buying the GM Goodwrench LM1 with 290HP. I like the sound of 300 better, so what's the easiest mod for 10 more ponies? 
Les
Les350 HO motor, $1,650 290HP. Porting/polishing the heads to the intake alone will get you 10+ hp.... cost $0.00
GM hotcam & valvesprings $350.00
1.6 roller rockers $250.00
That combo makes more HP than my street tires can handle!!!
Last edited by jcswm; May 14, 2005 at 12:47 AM.
Instructor
Joined: Dec 2004
Posts: 230
Likes: 6
From: Washington DC
Originally Posted by 68/70Vette
PS. That Edelbrock engine really had an awesome sound, even at any rpm. I wish I had know more about the Edelbrock crate engine quality before I bought my GM ZZ4.
What.. the ZZ4 doesn't have a old school muscle sound?
Melting Slicks
Joined: Apr 1999
Posts: 2,010
Likes: 3
From: Moon Twp. PA USA
Originally Posted by 81 Vette
That really all depends, running a running a tight quench wont create any major problems depending on what your piston-to-wall clearance is, the smaller and tighter the piston is, the tighter the quench you can attain. Also, Depending on where your deck height on the piston is, negetive and to what extent, that has a lot to do with determining the thickness of gasket you can use. Say it was a negetive .005 deck height piston, with a .027 cometic gasket, youre looking at overall .033, which is VERY tight true, but if this is a hipo engine using high very quality parts and tight wall clearences, you should be ok. Now if this is a slightly more run of the mill sort of engine where clearences havent been checked to be that tight, then I would say moving up to a .030 or .036 might be more advisable. A lot, if not most hipo engines use a final clearence of around .040 after deck height is factored in, Ligenfelter engines run a .037 after deck height.
Not to bust A**, but are YOU running a .027 quench?
Piston side clearance is .0015 on my work in progress 383 and the DECK HEIGHT (down in the hole) is +/- .001. I am getting a calculated static CR of 10.19 and an actual quench of .040 to .041. If I can reduce the quench to .030 by a thinner gasket (still less than your .027 figure) I can pick up some on the static CR.
Thread Starter
Race Director
Joined: May 2003
Posts: 11,814
Likes: 9
From: Science Bitch! Mississauga, Ontario
Canadian Events Coordinator
OK, I decided to get the 330 H.O. engine instead, so I don't care about 10 more HP. I will swap cams instead to make about 50 more horse.
All is good.
All is good.
Burning Brakes
Joined: Sep 2004
Posts: 917
Likes: 0
From: Vernon British Columbia
St. Jude Donor '05
First C3 General Poster!
Originally Posted by glen242
Well, you said .037 deck height and I assume you mean .037 quench?? Now if that is true (the .037 quench) that is a far cry from your stated .027 quench.
Not to bust A**, but are YOU running a .027 quench?
Piston side clearance is .0015 on my work in progress 383 and the DECK HEIGHT (down in the hole) is +/- .001. I am getting a calculated static CR of 10.19 and an actual quench of .040 to .041. If I can reduce the quench to .030 by a thinner gasket (still less than your .027 figure) I can pick up some on the static CR.
Not to bust A**, but are YOU running a .027 quench?
Piston side clearance is .0015 on my work in progress 383 and the DECK HEIGHT (down in the hole) is +/- .001. I am getting a calculated static CR of 10.19 and an actual quench of .040 to .041. If I can reduce the quench to .030 by a thinner gasket (still less than your .027 figure) I can pick up some on the static CR.