[special-k]

I have a 88 G20 Chev van witha 350 TBI /700R trans and 3.73 rear end. The rearend howls enough that I put heavier oil to quiet it down. A friend has a 81 Chev van 12 bolt rear end with 3.08 gears and posi. Does any one know if this bolts in and do you think the taller gears will kill any pep the van does have . It's not exactly a fire breather now LOL Any tips will be appreciated.

 

[SSedan64]

Mounts are probably different. 3.08 will kill performance and MPG with the 700R4's .70 O/D your final ratio would be 2.156 compared to 2.611 with the 3.73 gears. Engine rpms would probably be to low for cruising.

 

[special-k]

Yeah thats what I'm afraid of. It actually get decent mileage now and pulls a small trailer o-k so I definitely don't want to go in the wrong direction. Thanks

 

[fast68]

doubt its 3.73 most likely it is the common 3.42

the RPO sticker on the van will list the ratio code



according to interchange info it is '88-95 on the 1/2 ton full size van rear axles

for some reason dont know why

same as with the pickups ets

 

[special-k]

I have the original order sheet showing a 3.73 ratio. The original owner was a packrat who saved every piece of paperwork for it. I was told the p/u was narrower than the van but I'll have to go out and do some measuring. Most of the other chassis parts go back to the older series of p/u's