Hello all, making a post here for a friend of mine who's building a 91 350 TPI Z28...

He's got the whole motor complete, suspension, etc. He chose to go with a 3.73 gear. Recently, he acquired an 80's era disc brake rear, complete with 3.42 gears. Now that he's ready to get the project on the road soon, he's thinks he needs to go with a custom chip. On the form for the chip, it asks what your gear ratio is. Does it really matter for the chip burn? The reason he's concerned is that the 3.73's are in right now, but if it turns out to be too much gear for him, he wants to be able to fall back on the 3.42's that are in the disc rear (when he gets around to installing it) without having to get a re-burn for his chip.

Related question, not sure if it belongs here, but... What all does he need to do to swap his stock 91 drum rear with the 80's vintage disc rear?

Thanks guys...
Matt

 

ttt...

 

OK, so I invested some time on the board into reading about PROM's... it looks to me like gear ratio should have nothing to do with a custom chip. Am I correct? Also, it looks like everybody is in agreement that a custom chip is a waste of cash... Hey, just a Ford guy here trying to help a GM buddy out... ha!