The Stovebolt Site Forums The Shop Area Engine Shop 308 differential

can anybody tell me anything about a 308 differential? and what engs would be a good match to one

TIA

I have a 3.08 in my '55 1st Suburban with a GMC 270 and an SM420. It works real well as a daily driver, but pulling a trailer with it does not work as well as I'd like.

I have one in my '57 GMC half ton with a '68 Pontiac 400,and it works great. I also run 31" tall 16's on it. Might be right on the edge of too tall gears for any kind of work with a six,but the big Pontiac has pulled my 35 foot RV trailer just fine,even on hills. Remember,if you end up with too much gearing or too little power,you can adjust that a little with your tire sizes(diameters). I also noticed going from a 4.10 to a 3.08 gave me about 4 more miles per gallon,average.
Speed

You are forgetting one important thing,the tranny.If you use a regular 3 or 4 sp.tranny it should work just fine.However if you plan to use an Overdrive tranny,it will not work out well.with an Od trans.you will need a 3:73,or 3;90 rear.

Thanks guys

I was told by the po that he put a 308 behind a 400 sb and it appears to be a 420 tranny from what I can tell...I know it has a granny gear and I was thinking about some taller tires...
I have boats to pull but here in Florida it's mostly flat except for a few parts of cent & panhandle...I know you western guys are snickering...

at any rate I have had to take the po's word for most of what is in this truck but it does seem to run good...

he told me it was a 400 but not if it was a chev or pontiac and I haven't been able to catch up w/him and ask...still haven't found #"s on the eng to tell for sure