L92/L76 Conversion
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Joined: Sep 2005
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L92/L76 Conversion
Anyone got a link to all the parts I need, where to get them, recommended cams, steps involved, to do this with a '05 LS2.
Pretty sold on this after reading the GM high tech article, and looking at some results like Evilways.
I've found L92 heads on Ebay new for $850. Haven't found the L76 though. Do I need the L76 TB? LS2 is 86mm right, vs the 90mm that's on the LS3 right?
Want to get this done soon as the nice weather is here.
Pretty sold on this after reading the GM high tech article, and looking at some results like Evilways.
I've found L92 heads on Ebay new for $850. Haven't found the L76 though. Do I need the L76 TB? LS2 is 86mm right, vs the 90mm that's on the LS3 right?
Want to get this done soon as the nice weather is here.
Burning Brakes
Joined: Jun 2009
Posts: 977
Likes: 1
From: Voorhees NJ
First, the L92/L76 setup is an awesome one...I saw an L76 on the Forum for sale recently..SLP has both heads and intake...The LS2 has a 90mm TB...It goes with the L92/L76...I have this setup on my LS2...With headers and exhaust I got 504HP at the crank...I recently put on a blower through ECS...I left the cam stock because I wanted good drivability...With a good cam, L92/L76, you could get 500RWHP with headers/exhaust and a tune...Good luck
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Ah ok. Rocker arms and plates are kind of expensive and included in the kit from SLP, makes the price a little more justifiable.
Also the springs are included too so another $250. See where the $2200 comes from now. Still more than putting it together myself though I think.
I want to go ahead and get stuff ordered fairly soon. Since it's racing season already out here in the desert.
Also the springs are included too so another $250. See where the $2200 comes from now. Still more than putting it together myself though I think.
I want to go ahead and get stuff ordered fairly soon. Since it's racing season already out here in the desert.
Racer
Joined: Feb 2007
Posts: 313
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ready for the heads
I have done the cam, headers and soon will be adding the L92 heads and L76 intake. I am having Manley values with comp cam bee hive springs. Heads will be milled to get chambers to 64 cc and I am having the heads cleaned up with a grinder and hand rolled for smoothness. Intake and heads will be port matched. I have a list of all parts going into the heads.
The cam I have been using is a Comp XER273hr base grind that is a special grind DTE used. His grind is 224 / 230 with .581/.592 lift with 115 so very close to stock 273 grind.
I know others out there have this same setup as I know Phil did a lot of these. I found he did excellent work and this car has performed perfectly for 1.5 years since his work was completed. Any thoughts I can expect at the wheels after the install.
I will be retuning the car after the head install and I wish Phil could do it. Since Phil is no longer doing this type of work, I am looking for a tuner who is within three hours of Bettendorf, Iowa. Any help is appreciated.
The cam I have been using is a Comp XER273hr base grind that is a special grind DTE used. His grind is 224 / 230 with .581/.592 lift with 115 so very close to stock 273 grind.
I know others out there have this same setup as I know Phil did a lot of these. I found he did excellent work and this car has performed perfectly for 1.5 years since his work was completed. Any thoughts I can expect at the wheels after the install.
I will be retuning the car after the head install and I wish Phil could do it. Since Phil is no longer doing this type of work, I am looking for a tuner who is within three hours of Bettendorf, Iowa. Any help is appreciated.
Last edited by youout; Nov 1, 2009 at 12:28 AM.
Tech Contributor
Joined: Mar 2003
Posts: 12,094
Likes: 197
From: Colorado Springs, CO
St. Jude Donor '08-'09-'10-'11
Everything you want to know about L92 installs:
http://forums.corvetteforum.com/c6-t...cam-specs.html
The L92 heads and LS3 heads are the same and use the same TB as the LS2 or LS3.
Current best cam for use with them that I used is a 230XFI 234XER 114+2 LSA. It made 482rw 440rwtq on the last car I did with them but retains great driveability because it isnt a huge cam. They seem to really like the XFI lobe for the intake side. I like the use of the 224/230 cam from above but recomend the 224XFI/230XER 115lsa.
I port the L76 intake for 175.00 and the TB for 125 with the intake.
http://forums.corvetteforum.com/c6-t...cam-specs.html
The L92 heads and LS3 heads are the same and use the same TB as the LS2 or LS3.
Current best cam for use with them that I used is a 230XFI 234XER 114+2 LSA. It made 482rw 440rwtq on the last car I did with them but retains great driveability because it isnt a huge cam. They seem to really like the XFI lobe for the intake side. I like the use of the 224/230 cam from above but recomend the 224XFI/230XER 115lsa.
I port the L76 intake for 175.00 and the TB for 125 with the intake.
Last edited by SpinMonster; Oct 31, 2009 at 07:22 AM.
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I read through that whole thread. I had no idea about fly cutting. To be honest, that scares the **** out of me.
I have found a used ported L92/L76 with patriot .650 lift springs. I am thinking about pulling the trigger on them. The heads are milled to 67cc, which I guess would be pretty close to stock CR. With our ****ty 91 at best gas, I don't think I'd want to bump the CR anyway. And I kind of wanted to leave the door open for a SC at some point.
I know you said if you aren't going with a CR and a cam big enough to require fly-cutting, then these aren't worth it, but I also know Evilways is at ~450rwhp with .030" milled L92s, un ported.
That video speaks volumes though. It really did idle and drive like stock and get 30mpg cruising. My C6 isn't a daily driver, but it doubles as the road trip car, so that's very important to me.
I have found a used ported L92/L76 with patriot .650 lift springs. I am thinking about pulling the trigger on them. The heads are milled to 67cc, which I guess would be pretty close to stock CR. With our ****ty 91 at best gas, I don't think I'd want to bump the CR anyway. And I kind of wanted to leave the door open for a SC at some point.
I know you said if you aren't going with a CR and a cam big enough to require fly-cutting, then these aren't worth it, but I also know Evilways is at ~450rwhp with .030" milled L92s, un ported.
That video speaks volumes though. It really did idle and drive like stock and get 30mpg cruising. My C6 isn't a daily driver, but it doubles as the road trip car, so that's very important to me.
Tech Contributor
Joined: Mar 2003
Posts: 12,094
Likes: 197
From: Colorado Springs, CO
St. Jude Donor '08-'09-'10-'11
I read through that whole thread. I had no idea about fly cutting. To be honest, that scares the **** out of me.
I have found a used ported L92/L76 with patriot .650 lift springs. I am thinking about pulling the trigger on them. The heads are milled to 67cc, which I guess would be pretty close to stock CR. With our ****ty 91 at best gas, I don't think I'd want to bump the CR anyway. And I kind of wanted to leave the door open for a SC at some point.
I know you said if you aren't going with a CR and a cam big enough to require fly-cutting, then these aren't worth it, but I also know Evilways is at ~450rwhp with .030" milled L92s, un ported.
That video speaks volumes though. It really did idle and drive like stock and get 30mpg cruising. My C6 isn't a daily driver, but it doubles as the road trip car, so that's very important to me.
I have found a used ported L92/L76 with patriot .650 lift springs. I am thinking about pulling the trigger on them. The heads are milled to 67cc, which I guess would be pretty close to stock CR. With our ****ty 91 at best gas, I don't think I'd want to bump the CR anyway. And I kind of wanted to leave the door open for a SC at some point.
I know you said if you aren't going with a CR and a cam big enough to require fly-cutting, then these aren't worth it, but I also know Evilways is at ~450rwhp with .030" milled L92s, un ported.
That video speaks volumes though. It really did idle and drive like stock and get 30mpg cruising. My C6 isn't a daily driver, but it doubles as the road trip car, so that's very important to me.
Tech Contributor
Joined: Mar 2003
Posts: 12,094
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From: Colorado Springs, CO
St. Jude Donor '08-'09-'10-'11
Safety Car
Joined: May 2006
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From: St. Louis, MO
Tech Contributor
Is it always neccessary to flycut the pistons?... My buddy just bought a L92/L76 setup with an LG G6X3 cam, and this was the first I'd heard about flycutting.
Last edited by DSteck; Nov 11, 2009 at 09:57 AM.
Pro
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From: S. Jersey .............. Low 11sec club
St. Jude Donor '11
Spin, As far as the intake goes, I would like to use the LS2 style injectors. So when finding an intake can I use my old fuel rails or would I need the LS3 rails? Which rubber O rings would I use also? Do you have intakes yet? jt
Former Vendor
Joined: Jan 2007
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From: Lubbock Tx
The LS2 and LS3 use the same fuel rail. the difference in injector height is made up on the intake. We stock L76 and LS3 intakes for anyone in need, along with all gaskets, rocker arms, etc needed for the swap.
These heads can be GREAT with a cam that isn't big enough to need flycutting. My preference is actually really similar to that of Spinmonster, with a tad more exhaust duration.
These heads can be GREAT with a cam that isn't big enough to need flycutting. My preference is actually really similar to that of Spinmonster, with a tad more exhaust duration.
Tech Contributor
Joined: Mar 2003
Posts: 12,094
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From: Colorado Springs, CO
St. Jude Donor '08-'09-'10-'11
The valves on the L92's are heavy and need more than the comp 918 which has had more breakage than just about any other spring. Float is especially bad on the L92's because the P/V clearance is much tighter than with the smaller valved 243 style heads.
The springs arent the place to try to save money in an L92/LS3 build. On a related note, Manley race flow valves cost the same as the stock valves. They are one piece stainless and not 3 piece welded valves like the stock valves that can break away if they hit a piston during valve float. The Manley's are heavier and again need more spring.
The heads are great for budget builds but the limit of the saving should be in the core costs and not from safety parts like a dual spring in case one breaks. The 918's have quite a breakage history.
Tech Contributor
Joined: Mar 2003
Posts: 12,094
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From: Colorado Springs, CO
St. Jude Donor '08-'09-'10-'11
I just did another Ls2 GTO and used a 230/238 at the owner's insistance for more exhaust duration. It was the first LS2 with LS3's install that didnt cut the 470rwhp line. The issue thats counterproductive is the overlap. It kills driveability and these heads have massive issues with reversion due to the path of least resistance when both valves are open. The intake draws it back in. People ignore this fact and think that the heads need massive exhasut side help due to the advertised flow number for the ex side. It doesnt.
A side note; these heads work with huge cams too. They dont lose power at 236 intake duration unless the overlap is so huge that they suffer from reversion. You simply use a single pattern and it hits the 500rwhp mark on a wider than normal LSA. One such build ran a 10.6 at 132 with a 2 degree split near 237 intake duration. Another made 496rwhp with a 236/236 116LSA....4 degrees overlap.
A side note; these heads work with huge cams too. They dont lose power at 236 intake duration unless the overlap is so huge that they suffer from reversion. You simply use a single pattern and it hits the 500rwhp mark on a wider than normal LSA. One such build ran a 10.6 at 132 with a 2 degree split near 237 intake duration. Another made 496rwhp with a 236/236 116LSA....4 degrees overlap.