Is the SM420 A Good Tranny?
 

Well I have a 1967 283 with SM420 (atleast I think) and I am wondering if this is a good tranny. Thanks

I like them alot. My 66 C10 has the 420 behind a 292, and then a 250. Lets a 1/2-ton do pull/move things you would only dream of with a 3/4. The 7.02:1 1st gear is killer for rock crawling.

The second gear syncros are known for wearing out. So long as you double-clutch on the 1-2 shift, it will just keep on going. It won't put up with huge torque. Stick to a 283 or a 4.3L v6 at the most. Parts are getting scarce, so I would get a spare before you commit to the project - just in case.

Interesting tranny to put in an S10. Are you considering a solid front axle swap too?

Thats what I have is a 1967 283. What do you mean by double clutching? And what other newer tranny will fit my 283?