68 chevy stepside suspension questi

[Mwallis783]

I have a 68 c20, 292, 4speed w/granny gear. The rearend ratio is 4.10 or lower 8 lugs. Gets nothing for gas mileage. I am looking at swapping out the whole rear end with something like 3.08 or a bit higher 6 lug. My current suspension is a coil spring setup. My problem is I am finding alot of leaf spring rear ends. Anyone have any experience with this or can make any suggestions. Also this truck has 21,000 original miles on it so I am trying to avoid any modifications taht require cutting anything

 

[dvalentine]

RE: 68 chevy stepside suspension qu

A 67-72 will be your choice for a no-brains bolt in. You can use later leaf spring rears with very little trouble by welding in the needed trailing arm saddles on the transplanr after setting the pinion angle. Early Classic Ent carries them.

You might want to consider a lower than 308 ratio for that granny 4 speed. 330 is about as high as I would recommend. If you want to swap rears in hopes of better cruising speed or MPG, the answer lies in the trans, not the rear. Consider an overdrive setup if you want to retain the 4 speed, or a 700R4 if you want to swap to an automatic 4 speed.

DVal

 

[4wheelattitude]

RE: 68 chevy stepside suspension qu

If you are looking for more info on gear ratio to rpm you might try csgnetwork.com/multirpmcalc.html or a number of calculators out there to help you find where you need to be.

 

[CST20]

RE: 68 chevy stepside suspension qu

CHANGED THE REAR ON MINE WENT 3.73 HAD TO USE 73 3/4 TON VAN REAREND AND TO STAY WITH COILS YOU WILL NEED A CUTTING TORCH AND WELDER YOU,LL ALSO HAVE TO SHORTEN THE DRIVE SHAFT 2OR3 INCHES THE NOSE ON THE 73 REAR END IS LONGER .. THE PROBLEM IS BETWEEN 68&72 THE C20 0R 3/4 TON GM ONLY MADE TWO GEAR RATIOS 4.10 AND 4.53 ONE FOR AUTO TRANS AND ONE FOR STICKS AND IF YOUR ,S IS A 4 SPEED IT SHOULD BE A 4.53 ?