Hey, Im buying a 12 bolt this week for my 89 GTA w/L98 since my cars rearend is dying and Im not sure if I want to put 3.42s or 3.73s in my car. What would be the advantages of the two. After I put in the rearend i plan on building my 700R4 w/ a 26-2800 stall converter.
Thanks

 

3.73's are abit too deep for stock or mild TPI setups. and with 26-2800 stall, off the line performance will suffer as traction should be a big issue. 1st gear in the 700r4 is very deep and that first gear would go by really quick.

now for modded TPI and superram/miniram setups, where rpm ranges go to near 5000-6000 rpms+, then 3.73's would be nice.

3.42's however seem to be a great choice for TPI setups and the 700r4. good for highway somewhat too. and it should work really nice with the 26-2800 stall. modded setups will still like it too.

my L98 with just headers and exhaust pulls 1.8 60 foots on street tires with 2800stall and 2.77 gears......and that first gear goes by pretty quick. 3.73's probly would work ok, but would be just too deep by the end of the 1/4mile. 3.42's be near perfect.