700R4 to Saginaw 3-Speed Swap

[Colby83]

Mine has the 2.85 1st gear. I didn't go with the 3.50 1st gear version because I heard about how fragile it is due to the torque multiplication, and the drop from 2nd to 3rd would be undriveable behind a diesel (also the case for the 3.11 1st gear version). I remember reading that the 2.54 first gear version was used behind 396 trucks in '68 only or something like that. Stouter because of less torque multiplication but it would require even lower rear gears for equal pulling power in 1st, though I guess that's not really a concern with a big block.

Thanks for looking up the drivetrain/rear gear combos. I'll settle for 3.73 for now if that's what's in the 14 bolt I'll be swapping in, but if it's any taller I'm definitely going to regear it. I want my truck to pull like a 1 ton. I know I won't be able to legally pull more weight etc. etc. but still more torque sounds more fun than being able to cruise 5 mph faster on the highway.

 

[Colby83]

Back home from college. I installed the Hurst backup light switch earlier, and I gotta say, what a dogshit product. Out of the box, the bracket didn't put the switch remotely close to the 1/R shifter arm. After a lot of trial and error (read: bending and cursing), I got it to work. The plunger needs to be almost fully actuated for the switch to make contact, as shown in the second picture.

On another note, I got some great news. My dad's coworker is giving me the whole parts truck for free. I'm looking forward to seeing how my truck drives with proper gearing.

 

[DoubleDingo]

I would highly recommend adding heat shrink to each connection and securing the wires really well along the run they are routed.

 

[Colby83]

Good call on the heat shrink. I ran the wires through the cable guides on the driver side frame rail so I should be good there. I did the same thing with my lift pump wire last summer and it hasn't given me any trouble.

 

[Ricko1966]

For the next guy doing this I think I'd try using a pull style motorcycle brake light switch and a pull cable. They are a pull on switch. Waterproof, IDK seems like a good idea.