I have a 89 GTA with a L98 donor car that I want to install the longblock into my 91 GTA that had a LB9. I'm staying stock for now. I know I have to change the prom and injectors. I'm staying with the speed density intake NOT the MAF intake off the 89. Doing some research I found that the 88-89 L98 and LB9 has a slightly different cam in it compared to the 90-92 L98 and LB9. https://www.thirdgen.org/mods3 stock cams at the bottom of the page.

My questions are:

1. Will the slight difference in the 89 cam cause problems with the stock 730 ECM and L98 prom?

2. Should I install a 90-92 stock cam in the 89 L98?

3. Are the lifters, pushrods etc. the same in the 89 as the 90-92 L98?

Thx. in advance for any help.

 

The cam won't cause any problems.
I have a stock 92 350 cam if you're interested.

For clarification:
89 350 Maf
91 SD 305

You want 89 350 & SD in the 91?

If this is the case, you'll need to keep the SD ECM in the car and change the programming for cylinder volume amoung a few other things. Or you could just get a boneyard 350 ECM.

 

The 89 computer is different than the 90-92 computer. If you mean using the 89 computer to run the SD intake.

Is the 92 cam new or used? P/N on the cam? How much shipped to 30122?

 

I'm only using the longblock from the 89. I'm using the SD intake.

 

Re-read my post. I edited when I realized what you wanted to do. Sorry.

Used cam. PN - 10111773

I'll PM you with $$

 

I have 2 used 10111773 cams, so I don't need to buy another used one. Thx. anyways.

 

I have everything I need to do the swap. The cam, lifters, pushrods are what I have questions about. I'm pretty sure the cam is the only thing thats different.

 

The lifters, pushrods, rockers, etc., are identical in all factory roller cam motors from 87 on up through the vortec motors. I bought a brand new set of roller lifters from a member here that were for his 98 vortec motor, and they're identical to the original, 1988 lifters I removed from mine. Summit lists the same part# for all these motors. As far as the cams go, I sure as hell wouldn't go through the trouble to change it out. The differences between the two factory tpi cams are so miniscule, it shouldn't affect anything. Guys put considerably larger cams in SD cars than either of the factory ones using the factory prom without issue. There's only 2.5 degrees difference in duration between them, and like 2-3 thousandths difference in lift, which basically equals a bump on a gnat's a s s.

 

Thx. Pat for all the info.