L98 cam retro, HELP!
Thread Starter
Le Mans Master
Joined: Jul 2001
Posts: 6,252
Likes: 2
From: Silicon Valley Kalifornia
L98 cam retro, HELP!
Just found out that my custom cam is hitting my 4340 GM rods. I really don't want to undo the assembly I just finished putting together, so I fitted my old '85 cam and it clears the rods. Since I'm supercharging and need to pass smog...and need a great idle... (question).... Will a roller cam from an '87-'90 clear the rods since my '85 flat tappet cam clears them. The L98 cams were all very approximate in lift values...I think. Will my distributor gear be compatible with these '87-'90 L98 roller cams? HELP!
[Modified by GRX, 9:22 AM 5/31/2003]
[Modified by GRX, 9:22 AM 5/31/2003]
Le Mans Master
Joined: Apr 2000
Posts: 6,341
Likes: 1
From: Shelton CT
Re: L98 cam retro, HELP! (GRX)
The problem is that the '85 cam is a hydraulic, and the 86+ cams are roller.
To use a rolelr cam you have to get a roller retrofit kit. Special Roller lifters,
and a few other things. I was looking into doing that but it get's expensive fast.. (Cam/retrofit lifters/shorter pushrods/new rockers/cam button, and one more thing I forget the name about). Also you will need a new distributor gear if you change cam profiles..
To use a rolelr cam you have to get a roller retrofit kit. Special Roller lifters,
and a few other things. I was looking into doing that but it get's expensive fast.. (Cam/retrofit lifters/shorter pushrods/new rockers/cam button, and one more thing I forget the name about). Also you will need a new distributor gear if you change cam profiles..
Thread Starter
Le Mans Master
Joined: Jul 2001
Posts: 6,252
Likes: 2
From: Silicon Valley Kalifornia
Re: L98 cam retro, HELP! (MrNuke)
I already have a roller set up to install. Problem is the high lift lobes are barely hitting the bow-tie rods....
Cam is a ...
Lobe Lift:
Intake: .330” x 1.5 rocker= .495”
Exhaust: .343” x 1.5 rocker= .515”
Lobe separation: 114*
[Modified by GRX, 9:24 AM 5/31/2003]
Cam is a ...
Lobe Lift:
Intake: .330” x 1.5 rocker= .495”
Exhaust: .343” x 1.5 rocker= .515”
Lobe separation: 114*
[Modified by GRX, 9:24 AM 5/31/2003]
Thread Starter
Le Mans Master
Joined: Jul 2001
Posts: 6,252
Likes: 2
From: Silicon Valley Kalifornia
Re: L98 cam retro, HELP! (CFI-EFI)
You can grind the rod bolt heads for clearence. The "Chevrolet Power" book reccommends .050" clearence. Good luck, and...
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Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
Re: L98 cam retro, HELP! (GRX)
Question: Is it ACCEPTABLE to grind them on a home bench grinder with fine grit wheel?????
....OR PAY a machine shop to do it????
I realize I need to get everything BALANCED again...more money, dang.
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