Nearly 15MPG with 4.57's and no OD in a C30!

[66Submarine]

It's a DRW C30, but it's not the original third member (it was stamped '70 or something IIRC).

The third members are supposed to interchange between the 52/72, but I'm not what the difference is between the two--or if there even is any (I don't have any to check and they'd need to be the same era as mine, anyway).

There is some level of variation, though; AFAIK any third member bolts into any 52/72 housing, but the internal parts differ through the years. I.E., I saw someone the other day that tried to swap just the gears (why???) and found out they wouldn't work in his third member and the driveshaft had to be shortened for the new one. With a production run of 1947-1972 they certainly had time to change stuff up!

I know a little bit about them, but not really that much. There are a few 4x4 people that are pretty into them that know more about all the differences.

I figure if I ever manage to blow one up I'll just stick another third member in or swap the whole deal for a 14 bolt.