Hello all.

I have a factory stock 87 IROC with the 5.0 TPI motor (VIN:F, LB9) and T-5 manual trans. 3.45 locker. All factory stock. I understand that gm installed a slightly hotter cam for this engine/trans setup over the auto trans configuration. Best I've found was 202/207@.50, 114.5 LSA, but they didn't seem too sure.

I was wondering if anyone on here can tell me without a doubt exactly what my cam specs are? (Lift, duration, LSA, etc). ALL kinds of data floating around in them interwebs and I can't get a definitive answer.

Thanks for anyone's help on this as Google and GM were less than helpful. 🙄

Also, can anyone on here help me out, or point me in the right direction for reprogramming my EPROM?

 

Those specs look about right for at least one of the cams they used.

 

1987/1987 - GM #14093643 202/207 @0.050 - .404/.415 Lift - 114.5 LSA
1988/1989 - GM #10066049 207/213 @0.050 - .415/.430 Lift - 117.0 LSA
1990/1992 - GM #10111773 202/207 @0.050 - .413/.428 Lift - 114.5 LSA

These are the camshaft specs I got from 3rdgenformula.com

The lift numbers assume a 1.5 to 1 rocker arm ratio. The factory stamped steel rocker arms are probably around 1.46 to 1.

@Tuned Performance is the guy you want to burn you a new chip.

 

I picked this up here on the forum some years back.

 

Great info fellas! Thank you. And the chart helped a lot. It looks like my data was correct. I'm getting ready to burn a new EPROM and I needed that.

 

Glad you found the information you needed. And Welcome to the forum.