I know that off hand, the G92 had dual cats, so the exhaust could breath a little better, but 3.42 seems high for a TPI engine... at least from the factory. I seem to remember Pontiac used 3.23's in some too... though not sure what models / years....
Anyone have any performance data between the 3.08 and the 3.42's?

Raf

 

With the G92 package, the 305 cars got 3.42's, and the 350 cars got the 3.23's. The posi/disc rearend I put in my car came out of a 91 5.7 GTA w/G92 option, and it's 3.23 ratio. I don't have any documented comparisons between 3.08 cars and 3.42 cars, but it's pretty obvious that the 3.42's are better. Usually the only cars that got 3.08 ratio were the low performance L03 (TBI) cars with a manual trans.

 

I have the 350/3.27 gears without the G92 option. I think the dual cats in '89 were a mid year option.

3.42 gears work great with 350/auto cars. I would imagine they're perfect for 305 5 speeds. 3.08 is a little on the low side.