The Stovebolt Site Forums The Shop Area The HiPo Shop '61 rear end swap help

Hello and welcome! Being 16, I'm a newbie to custom work. Power steering brackets are the extent of my custom knowledge. The truck getting the treatment is a 1961 C20 with what I understand to be the 4.57 rear end. Before I get into it I need to know what exact rear end I'll need. I want to keep the 8 lug configuration and end up with a ratio between 3 and 3.5. From this website (http://www.chevytalk.org/fusionbb/showtopic.php?tid/237044/) and a few others it looks like I will be looking for a diesel 73-87 3/4 or 1 ton 14 bolt rear end, but (i think) even then I would have 1.5 inches more axle length on each side. Is there a frame size difference between years I should know about? Posts around here suggest there is a difference in size between 1960-1962 and 1963-1972 trucks. I know there are several other issues involved.. I feel I'm asking for a lot here, but I need your help! Any options, suggestions, information, and bumps are very appreciated. Thanks! -- Hunter

LMC truck makes ring and pinion sets non-DANA differentials, but only for 1965-1966, why would this not work in a '61?

The easiest option would be to get a 3rd member from a '68-'72 C20, usually with a 350 and automatic, which has the 4.10 gear. That would be a direct bolt in. Pretty much any other rear would require modification to work with the trailing arm/coil spring rear suspension in the '61. If you were to use a later rear, it would not necessarily have to come from a deisel truck, gas engine trucks use the same rear. For something narower, you might look at vans instead of pickups. 3.73 is a common gear on the later trucks, you might be able to get a 3.55 gear if you look at Dodge Dana 60s.

I took a look at them, they are for the '63 and later 12 bolt 1/2 ton rear, completely different animal than what you have.

The 4.10 bolt in sounds best if it's a bolt in. My goal is interstate speeds without swapping the tranny or the engine. I'll look into vans and the dodge rear ends.. thanks a ton!

the 4.1 ratio is too low for interstate, its only 8mph better, a gear vendor transission would give me the same final drive as a 3.55.... but it's a hefty 3 grand