hello... Well i have a 1991 firebird with an LO3 in it... now i bought a pair of heads off of a 89 ta. They are the tpi heads not the tbi... everyone tells me that they are a lot better heads. Now.... here is the issue. sence i havent ripped apart the engine yet.. i need to know how the bolts are set up on out heads... the ones of the tpi have :

. . . . . .
straight down sideways straight down


ive been told that mine might be

. . . . . .
down down down

i dont want to waste my 200 $'s to get them machiened and a valve job done if they wont fit.... Please help and please be sure.

 

The 89 Cast iron TPI heads should have the same intake bolt pattern as the 91 TBI heads. It's the alluminums and pre 86 heads that are different and the Vortecs that are a lot different.