3 speed vs 4 speed Saginaws

[lilsumo]

My 3 speed has a bent main shaft and locating a new shaft or tranny in time has become cumbersome. I did however locate a 4 speed.

this is going in a sport mod and was wondering if the 4 speed will be ok. I heard I'd have to take off in 3rd cause to get first and 2nd I would have to add another shifter. With a 5:43 gear i don't see any problems.

Could/Should I disassemble the 4 speed and stick the main shaft into the 3 speed? or is that even possible? I think they are the same but would like some clarity.

Are the 3 speed and 4 speed the same length?

Thanks for any help.

[C10]

We run the 4 speed aluminum case. It has first and 3rd removed. All we did was use the regular shifter and hooked it up to the forward gears, and installed a 3rd straight rod through the interior hooked to reverse. All yah had to do is push or pull the rod for reverse and there wasnt 3 shift levers to get confused on. Oh yeah there the same length too .