More performance for my 1980 L82
Race Director
Joined: Jan 2003
Posts: 15,176
Likes: 88
From: State of Confusion
I believe the Cross-Fire came equipped with camshaft # 12364051, a hydraulic grind listed as .390"-lift intake, .410" exhaust, and duration specs of 195* intake, and 202* exhaust, @ .050" lift, so now the valves are 'tricked' into thinking it is a cam with .414" intake and .448" exhaust lift, while adding a very few degrees @ .050"-lift, too.
Hope this helps!
Le Mans Master
Joined: Mar 2004
Posts: 7,503
Likes: 1,511
From: Little Rock AR
The 1.6:1 ratio rocker arms, CompCams P/N 141816, were a direct bolt-on, and required no grinding of the slots on the OEM / L-83 heads:
I believe the Cross-Fire came equipped with camshaft # 12364051, a hydraulic grind listed as .390"-lift intake, .410" exhaust, and duration specs of 195* intake, and 202* exhaust, @ .050" lift, so now the valves are 'tricked' into thinking it is a cam with .414" intake and .448" exhaust lift, while adding a very few degrees @ .050"-lift, too.
Hope this helps!
I believe the Cross-Fire came equipped with camshaft # 12364051, a hydraulic grind listed as .390"-lift intake, .410" exhaust, and duration specs of 195* intake, and 202* exhaust, @ .050" lift, so now the valves are 'tricked' into thinking it is a cam with .414" intake and .448" exhaust lift, while adding a very few degrees @ .050"-lift, too.
Hope this helps!
Maybe it was a carbed '81 Vette? Somebody help me here.
FWIW
-Mark.
Last edited by stingr69; Nov 19, 2008 at 02:18 PM.
Race Director
Joined: Jan 2003
Posts: 15,176
Likes: 88
From: State of Confusion
I know when I first bought this pig, common-thinking at the Cross-Fire Forum site was that the 051-cam came in production L-83s
I know that my Corvette now pulls very hard to 5000 RPM, and shows no-signs of nosing over when I make the 2-3 shift
(with just 3 runs made in preparation of 3 weeks of racing, had I known I'd have more-time to make additional runs, I'd have tried shifting at 5500, to make a viable side-by-side comparison:
if I could've held the 700R4 in 1st Gear longer and let it wind-out further, I believe the car would've run even quicker to 330' and 660')
if this motor does have the 962-cam, that'd make more-sense.
Le Mans Master
Joined: Jun 2004
Posts: 6,231
Likes: 65
From: Seattle WA
St. Jude Donor '14
The L-82 cam is P/N 3896962 .450/.460 lift, 222/222 (@.050); given the published HP numbers I can't imagine the L-83 having the (in)famous "390" (3663152 and other numbers), .390/.410, 280/288) cam.
Race Director
Joined: Jan 2003
Posts: 15,176
Likes: 88
From: State of Confusion
I submitted P/N 141816 in my above post straight from the receipt I got from the project from the shop, so I have sent an e-mail to RevXtreme, asking for verification of which rocker-arms we have used, if my copy of the paperwork has a typo-error, if we need to make a change, and the reasoning for using these particular pieces.
Good-catch, Brent!
Race Director
Joined: Jan 2003
Posts: 15,176
Likes: 88
From: State of Confusion
MN-Brent has sent me a Private Message, informing me that the CompCams P/N 141816 is listed as 'self-aligning for '87 & later heads, and that P/N 141616 should be the correct rocker-arms for the stock L-83 heads'.
I submitted P/N 141816 in my above post straight from the receipt I got from the project from the shop, so I have sent an e-mail to RevXtreme, asking for verification of which rocker-arms we have used, if my copy of the paperwork has a typo-error, if we need to make a change, and the reasoning for using these particular pieces.
I submitted P/N 141816 in my above post straight from the receipt I got from the project from the shop, so I have sent an e-mail to RevXtreme, asking for verification of which rocker-arms we have used, if my copy of the paperwork has a typo-error, if we need to make a change, and the reasoning for using these particular pieces.
Just got it from a post on DC that a guy had done some similar mods….but retained the cross-fire induction.
So as his was an 82 & he got good results, I used the same part #.
So as his was an 82 & he got good results, I used the same part #.
Le Mans Master
Joined: Apr 2001
Posts: 5,000
Likes: 1
From: Minneapolis, Mn USA
In doing my own research to do this job, if you dont use any pushrod guides, then the self aligning 87 and later RRs can work in earlier applications apparently.
Maui Tom on the CFI forum showed me how he did his and it looks as if 82s did not come with the GM psuedo non-hardened pushrod guides from the factory. Since there is no guides, it seems OK to use self aligning rockers.
Theres also the roll of the dice on whether the pushrods rub the head with 1.6RRs. There is the special tool to handle drilling these out if they do. I hope I can get lucky here.
These are Comp Cams 1.52s below on the 82s L83 OEM head, which should be similar to the L82 head, minus valve sizing.
Glen-take a pic of your roller rocker set-up. I'd like to copy it.
Maui Tom on the CFI forum showed me how he did his and it looks as if 82s did not come with the GM psuedo non-hardened pushrod guides from the factory. Since there is no guides, it seems OK to use self aligning rockers.
Theres also the roll of the dice on whether the pushrods rub the head with 1.6RRs. There is the special tool to handle drilling these out if they do. I hope I can get lucky here.
These are Comp Cams 1.52s below on the 82s L83 OEM head, which should be similar to the L82 head, minus valve sizing.
Glen-take a pic of your roller rocker set-up. I'd like to copy it.
Last edited by MN-Brent; Nov 30, 2008 at 11:53 PM.
Pro
Joined: Jun 2005
Posts: 584
Likes: 61
From: USA
I have a '78 L82, well, it used to be "L82", before the BBC went in.
it was bone stock when i got it, minus the cat conv. The biggest improvement right-off-the-bat was some full-length (i.e. not "shorty") headers and true full 2.5" dual exhaust w/ Flowmasters, but take your pick of mufflers, a zillion choices await you. Of course, shortly after that, the intake & carb was replaced with a Holley high-rise early LT1/Z28 style manifold (no EGR), and the requisite Holley 600 CFM 4-bbl double-pumper (4776?). Even with the L82 cam, at that point, it was a blast to drive. drove it like that for a few years before big-block fever took over.
Shucks, that L82 SBC was more fun to drive than my current 540, got to drive it more often, at least. oh well.
it was bone stock when i got it, minus the cat conv. The biggest improvement right-off-the-bat was some full-length (i.e. not "shorty") headers and true full 2.5" dual exhaust w/ Flowmasters, but take your pick of mufflers, a zillion choices await you. Of course, shortly after that, the intake & carb was replaced with a Holley high-rise early LT1/Z28 style manifold (no EGR), and the requisite Holley 600 CFM 4-bbl double-pumper (4776?). Even with the L82 cam, at that point, it was a blast to drive. drove it like that for a few years before big-block fever took over.
Shucks, that L82 SBC was more fun to drive than my current 540, got to drive it more often, at least. oh well.
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Race Director
Joined: Jan 2003
Posts: 15,176
Likes: 88
From: State of Confusion
Best I could do on short-notice in the early-morning light, and this picture won't reveal much
although it is close, it appears there is room on the side of the slot closest to the rocker-stud:
bumping the motor over a complete revolution shows no pushrods with damage in that area, the oil looks fine, and when each lifter is on it's lobe's base-circle, each pushrod spins easily by finger without contacting the slot (at-least on THIS side of the motor), so we'll see what happens.....
although it is close, it appears there is room on the side of the slot closest to the rocker-stud:
bumping the motor over a complete revolution shows no pushrods with damage in that area, the oil looks fine, and when each lifter is on it's lobe's base-circle, each pushrod spins easily by finger without contacting the slot (at-least on THIS side of the motor), so we'll see what happens.....
