The Stovebolt Site Forums The Shop Area Driveline tranny rearend switch?

Just trying to start planning my summer project and need a lot of advice. I have a 1960 c60 Chevy that I am currently using. I have taken the original engine out and put a 350 in it. I cut 2 feet out of the frame and shortened it. I put a really heavy welding bed on it and I use around the farm and do odd welding jobs for the neighbors. Now finally to the question. I am currently rebuilding a 348 and I think it's going to be a runner. Now I am sick of going 40 mph every I go. With new engine I'd like to show off a little. Can I rebuild trans and rear end or should I replace them?

Hy windmillguy, once you identify which brand and series of differential you have, you should be able to find a rebuilt diff. with a ratio that will get you more top speed, the supplier may want your old diff as a core to exchange for the rebuilt diff.. Do you have a single speed or two speed diff at the moment? One other swap to consider is installing a transmission with overdrive as high gear, the NV4500 might be a candidate for that, but you would have to check the GVW of the vehicles they were designed to be used in, hope that helps.

Switching to the nv4500 will get you to 55 mph at the same rpm that you were running with the old tranny. If you put the 348 in you may not want to spin it as hard as the 350.

Ask your self how fast do you really want/need to go?

In Wyoming 55 isn't fast enough for the highway but it doesn't sound like you are going take it out on I80.

This all assuming your current tranny is 1:1 in high.

Thanks for the advice as usual I don't have enough info. I'll get to work on getting to know my diff better. I'd like to go fast enough to pass somebody at least once. And yes I do have a 2 speed diff. thanks