Deciding on a 4-speed Transmission

[argonaut]

I'm trying to decide which transmission will go back into my 66 when I re-install the drivetrain. I have two sm420's available and an sm465. The motor is a bbc 402 and I'll be using a divorced T221 rockwell transfer case.

Any reason why I should use one vs the other?

The truck will be mainly used on the street with some off road use on weekends, but no crazy wheeling over boulders and up shear cliff faces...

[Redcap]

SM420 7.05 3.57 1.70 1.0

SM465 6.55 3.58 1.57 1.0

They are both tough transmissions, though I think it is easier to find parts for the SM465.

[DieselEater]

You won't use 1st gear on either anyway so you might as well have the lower gear of the SM420 for occasional specialty use...

If you've ever run an SM465 up a steep grade in Colorado with a load of aggregate and a sub-500HP engine, then you know that the jump from 3rd to 4th is like too far...You over rev in third, and almost die out in 4th.

The point is, you get a benefit in two areas with the 420 which makes this decision a no brainer...

BTW...I'd like to get my hands on your other 420...



A.........