C4 Mild - Inexpensive Upgrades
Le Mans Master
Joined: Oct 2007
Posts: 9,698
Likes: 3,468
From: Akron Ohio
2025 Corvette of the Year Finalist - Modified
2024 C5 of the Year Winner - Modified
2023 C5 of the Year Finalist - Modified
2022 C5 of the Year Finalist - Modified
St. Jude Donor '09-'10-'11
Camshaft ($300)
Headers ($500 - 800)
1.6 ratio roller rockers ($150)
Exhaust (varies)
Porting heads ($1000)
$300 does not get you 35 HP. Real HP is not free, but it's not extremely expensive, etiher. My LT1 made 414 to the wheels following this recipe, which equates to 480 HP at the crank assuming 15% drivetrain loss. Guys like Tom400CFI are where I got my information.
This is from on old post which a search would easily uncover:
Recipe for 425 to 450 CRANK HP:
Corvette 350 LT1 with flattop pistons. (Stock components will work)
LT1 Alum. Heads that flow over 260cfm/intake, 190 cfm/exhaust. (Pretty easy to achieve through CNC or hand porting by a pro)
1.75" Full length headers with dual 2.5" exhaust and hi-flow mufflers.
Relatively large camshaft with at least 236 degrees of duration @ .050" and .550" to .585" lift, depending on the ported head's limit. (With no emissions and decent exhaust this can be a single pattern cam with 110 or 112 degree LSA)
52mm or larger throttle body with modified air filter assembly.
24lb to 30lb injectors, depending on who programs/tunes your PROM.
.029" headgasket to get 10.75-11.0:1 compression, depending on final combustion chamber size after head porting/milling.
MSD 6A or 'bigger' and a full-size coil for top end spark energy.
Electric waterpump and an aluminum flywheel will also help the 'bottom line'.
Comp Cams Pro Magnum Roller Rockers and measure for custom length pushrods.
Headers ($500 - 800)
1.6 ratio roller rockers ($150)
Exhaust (varies)
Porting heads ($1000)
$300 does not get you 35 HP. Real HP is not free, but it's not extremely expensive, etiher. My LT1 made 414 to the wheels following this recipe, which equates to 480 HP at the crank assuming 15% drivetrain loss. Guys like Tom400CFI are where I got my information.
This is from on old post which a search would easily uncover:
Recipe for 425 to 450 CRANK HP:
Corvette 350 LT1 with flattop pistons. (Stock components will work)
LT1 Alum. Heads that flow over 260cfm/intake, 190 cfm/exhaust. (Pretty easy to achieve through CNC or hand porting by a pro)
1.75" Full length headers with dual 2.5" exhaust and hi-flow mufflers.
Relatively large camshaft with at least 236 degrees of duration @ .050" and .550" to .585" lift, depending on the ported head's limit. (With no emissions and decent exhaust this can be a single pattern cam with 110 or 112 degree LSA)
52mm or larger throttle body with modified air filter assembly.
24lb to 30lb injectors, depending on who programs/tunes your PROM.
.029" headgasket to get 10.75-11.0:1 compression, depending on final combustion chamber size after head porting/milling.
MSD 6A or 'bigger' and a full-size coil for top end spark energy.
Electric waterpump and an aluminum flywheel will also help the 'bottom line'.
Comp Cams Pro Magnum Roller Rockers and measure for custom length pushrods.
No aftermarket filter setup makes any gains on a stock or slightly modified engine. Cam and headers will be tremendous all for less than $1K (even lower depending on header type).
Le Mans Master
Joined: Jun 2009
Posts: 6,528
Likes: 752
From: South Dakota
I agree cam and headers are usually the best bang for the buck to increase power.
The higher ratio rockers are an easy and relatively inexpensive mod that helps a little by slightly increasing the cam. I have done that on a couple too. If you are changing cams though you may be able to find the profile you want without the added ratio.
I have also heard that the LT1 stock manifolds and exhaust are pretty good. The gains from headers will show more effect the wilder the engine is.
Heads may be the constraint to making a lot more power. A good porting or aftermarket like the AFR's can really do good, but head work/aftermarket heads can be expensive.
The higher ratio rockers are an easy and relatively inexpensive mod that helps a little by slightly increasing the cam. I have done that on a couple too. If you are changing cams though you may be able to find the profile you want without the added ratio.
I have also heard that the LT1 stock manifolds and exhaust are pretty good. The gains from headers will show more effect the wilder the engine is.
Heads may be the constraint to making a lot more power. A good porting or aftermarket like the AFR's can really do good, but head work/aftermarket heads can be expensive.
Race Director
Joined: Feb 2003
Posts: 16,475
Likes: 270
From: Kingman AZ
Cruise-In VII Veteran
Cruise-In VIII
St. Jude Donor '06-'07-'08-'09-'10-'11-'12-'13-'14-'15-'16
Local crew member was having the same discussion about his yellow 93 vert. Looked nice but was not real exciting to drive.
Solved the problem by purchasing a used yellow C5 Z06 from Berger Chevy in Grand Rapids.
Now you can't wipe the smile off his face. And, he kept the vert for cruising. Win-win.
Solved the problem by purchasing a used yellow C5 Z06 from Berger Chevy in Grand Rapids.
Now you can't wipe the smile off his face. And, he kept the vert for cruising. Win-win.
Team Owner
Joined: Aug 2004
Posts: 21,543
Likes: 3,216
From: Park City Utah
Scaryfast did an excellent job outlining gains for cost.
If you want an intake for looks, I can't argue with that.
Melting Slicks
Joined: Oct 2005
Posts: 3,178
Likes: 5
From: Daleville Indiana
St. Jude Donor '08
Doing the work myself got me 426rwhp and 396rwtq and cost about $5k.
Dyno tune, Crane Gold 1.6RR, SLP claw, AFR 195 heads, 11.0:1 compression, LT4 intake, LPE 219, Electric waterpump, LTCC, EM Headers, Magnaflow 3"cats and X-pipe, Borla mufflers and AC delete with a stock short block.
Dyno tune, Crane Gold 1.6RR, SLP claw, AFR 195 heads, 11.0:1 compression, LT4 intake, LPE 219, Electric waterpump, LTCC, EM Headers, Magnaflow 3"cats and X-pipe, Borla mufflers and AC delete with a stock short block.
Safety Car
Joined: Jul 2001
Posts: 4,871
Likes: 15
From: Detroit's West Side MI
DId you ever figure out your tranny issues?
Safety Car
Joined: Jul 2001
Posts: 4,871
Likes: 15
From: Detroit's West Side MI
I guess I should have been more clear in my post on page 2. Each of those things on the list can provide some gain, but you really have to put it together to get big numbers. Just a cam will give a nice "bang for the buck" improvement, but if you don't also improve your cars breathing you're only getting half of what you could. Head porting and better exhaust finish the deal. The other stuff is mostly support, like injectors, roller rockers, etc. to allow the cam to do it's work.
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Le Mans Master
Joined: Oct 2007
Posts: 9,698
Likes: 3,468
From: Akron Ohio
2025 Corvette of the Year Finalist - Modified
2024 C5 of the Year Winner - Modified
2023 C5 of the Year Finalist - Modified
2022 C5 of the Year Finalist - Modified
St. Jude Donor '09-'10-'11
Dude you have no idea what's happened to me. I've become obsessed, I now have 4 LSx's. I am now looking for cars to put them in. I have the magic LS6 that I put into the C4 last year, I have a 24k miles LS2 I picked up with a friend, we also have an LS6 ASA motor that's going into something...plus the LS2 in my C6 is tired so it needs replacement. I am going on that show "Hoarders" because of this new fixation.
DId you ever figure out your tranny issues?
DId you ever figure out your tranny issues?
Le Mans Master
Joined: Oct 2008
Posts: 9,758
Likes: 49
From: Houston Texas
Dude you have no idea what's happened to me. I've become obsessed, I now have 4 LSx's. I am now looking for cars to put them in. I have the magic LS6 that I put into the C4 last year, I have a 24k miles LS2 I picked up with a friend, we also have an LS6 ASA motor that's going into something...plus the LS2 in my C6 is tired so it needs replacement. I am going on that show "Hoarders" because of this new fixation.
DId you ever figure out your tranny issues?
DId you ever figure out your tranny issues?
Yes I did, I had the trans and the converter rebuilt. They are ready to go back in as soon as I get off my butt. We have a 4 month old and I get like 4-5 hrs sleep and have been working 10hr days
Last edited by ch@0s; Jan 18, 2013 at 02:00 PM.
