Im putting a 13B with holley carb and transmission on my 85 gsl that has a 12A and I wanted to know if I need to upgrade the computer, or can I run it stock no problems?

 

this is not that kinda of suggestion...moving to appropriate section...

 

There is no computer control on cars with carburetors. Just swap the 12a (or a gslse) front cover and an oil pan from a gsl-se. You also need a header for a 13b. 12a-13b motor mount adapters if you use the 12a front cover. Good luck.