Need some help, rear end swap

[Devil Pup]

Alright so I have a 1969 C20 with a 350 and th350 running 4:10's in the rear. I plan on bagging the truck within the next few months but i want to change to 1/2 ton and 4 link the rear. I want to increase my mpg and take strain off the motor on the freeway. I dont have a tach but when running around 60-65 on the freeway it sounds like the truck wants to blow up. "literally" I wanna know what 1/2 ton axle "out of what year model truck" would you guys reccommend and what gear ratio i should look for. "I wanna swap a 700r4 for the trans but that depends if i have the cash to do it at the same time. but I will be doing a 700r swap for sure in the future. just a matter of time. anyway the plan is to bag the truck on 20's possibly 22's in the rear, I wanna know what the best rear end/gear ratio would be to put under this for cruising and mpg. Thanks for any help guys.

[MARKDTN]

I would go in reverse and do the trans before the rear. The deep overdrive of a 700R4 (.7) will make your 4.11 be a 2.87 in OD with the converter locked but still give you a stout out of the hole for towing or hauling.

[Devil Pup]

ok i see your point in that. only question is I have to change my rear before i bag it because im 4 linking with a custom kit. so if i bag it first then swap my rear ill have to do a new 4 link. If i could change both the rear and the trans what is the best option? "ie. gear ratio and what truck should i pull it from?

[Devil Pup]

or should I just stick with the 4:10's?

[eagleuh1]

Actually you'd just have to weld the brackets on a new rearend at the future date if you decide to change rearends. You could still keep the 4-link arms.

[Devil Pup]

ok that makes sense. Well when i do change the rear end what gear ratio would anyone recommend?

[Longhorn Man]

I would go with a 3.73 rear

[Devil Pup]

Originally Posted by Longhorn Man

I would go with a 3.73 rear

do you happen to know what year chevy 1/2 ton i can pull this out from under?

[dave2953]

I would say any 73-87 and same year 'burbs including 88-91. My rear is from a 79 C-10. I just had to change the perches since the donor was a leaf spring truck. The driveshaft bolted to the rear end differently, too. Straps as opposed to u-bolts.