I have a 91 vert that came with an automatic tranny, but i swapped out to a manual. From what i understand the autos had the 3.90 rears and the manuals had the 4.10 rears and the gtu had 4.30. But i read somewhere that all verts had the 4.10 regardless of the tranny. Anyways I want the 4.30 rear, because i rarely even go faster than 80 mph and 90% of my driving is on curvy back roads where acceleration is everything. So I want to swap out the rear myself. I am preaty handy with the wrench as I've done all the mods to my car on my own except the tranny swap (KDR). So, can I do this on my own? Is it easier to get the whole gtu rear or just a ring and pinion set and install it in mine?

 

too bad you didn't have a 89 or 90 vert, those came with 4.10 wether or not they had autos.

Yeah the 91 came with the 3.90.

I haven't done the 4.3 conversion myself, but it looks very straight forward. You just have to disassemble the diff.

 

Would gears really help you accelerate quicker on backroads? I mean its fine from a standstill but above that, what do you get with the gears? Its quicker in each individual gear but you have to shift sooner. Just my .02.