First off – What a fantastic web site!!

I currently have a '77 GMC 3/4ton Crew Cab that I’ve owned for the past twenty-five years. I’ve painted it outside twice and replaced the doors fenders and hood but time has finally caught up with it. It spent it’s early years as a truck on a Texas Cattle Ranch and the winter salt has done it in.

I want to keep the 502 crate motor I put in it as well as the turbo trans. Both have very low mileage on them. The 502 is the high torque towing engine. I’ll also swap over the over load springs on the '77 to the '64-'66. I need another towing vehicle for my toybox trailer and I’m looking at the 1964-66 GMC/Chevy 3/4ton trucks. . I understand in 66 the 3/4ton GMCs went to leaf springs on the rear and Chevy stuck with the coils. I love the body style on these trucks and because of the year I won’t have to worry about the smog inspection here in the People’s Republic of California.

The toybox trailer (not a fifth wheel) is 21’ and loaded weighs about 7-8,000 lbs. I plan on swapping the brakes front and rear to power disc. and installing power steering. One of the things I don’t like on my '77 is the full floating rear axle which requires pulling the axles to do the drum brakes. I also didn’t have much luck looking for a disc conversion for the '77 rear end.

My Questions are:

1. Will my 502 and turbo trans fit in the 64-66 trucks?
2. Is there a problem pulling that much weight with the older 3/4ton trucks?
3. What rear end (not ring and pinion) would you recommend for this application that would be an easy fit? Concerning gearing of the rear end my '77 has 3.73 gears and I’d like something a little taller for lower RPMs at cruising speeds. Gearvendor over drives are a little pricy.
4. Would I have to stiffen up/reinforce the frame any. I understand that in 67 they went to thicker frame rails.
5. How about gas tanks? My '77 has saddle tanks with a total capacity of 40 gals. What gas tank options do I have for tanks that fit inside the frame rails that will give me a reasonable driving range?

Any assistance will be greatly appreciated! I’d like to be doing the conversion by early summer. That way I can start now with accumulating the parts needed and of course a '64-'66 truck.

Thanks again!
Gunnar
So. California

Last edited by Gunns; 01/25/2012 10:17 PM.