The Stovebolt Site Forums The Shop Area Engine Shop 216 top speed- Part 2

By the way, my truck is a 3/4 ton and the rear axle is not 4.11:1 or so I am told (I will have to look it up in the manual). Anyway I have been looking for a 3.55:1 conversion at various sites yet have seen nothing for the 3/4 ton pickup, just the half. Anyone know of a source or any suggestions. Did the 3/4 pickup operate at even lower highway speeds than the half? Thanks in advance.

Chris, I had a 84 Chevy G20 van with a 4 speed manual overdrive trannie behind a 6.2 diesel. Was ordered that way. I was thinking that might fit your truck. But after getting started with this post I remembered, the G 20 is rated as a 3/4 ton truck, but had 5 bolt wheels. So no good for your truck. This type of overdrive trannie might help a lot though. Probably would depend on what kind of loads you haul. We pulled loaded car trailers, with the van loaded to the gunnals with people and luggage, to Flordia and around Colorado. The low gear isn't very low, takes some effort. And when you stick it in reverse you better know where you are going, cause you get there in a hurry. The torque of the diesel may have helped with this problem. But the low and reverse may have been caused by the diff gearing. I don't remember what it was. I have seen this trannie behind a 318 in a Dodge van also, so there should be some around. Still have the trannie in the shed. If you want numbers off of it let me know, I'll look for them. The one I have will probably go in my 41 which will be a 3/4 ton.

Your gear should be a 4.57. With 30" tires, it puts 40 mph at about 2,000 rpm. There is no easy or cheap solution for a good gear ratio. You can get 4.10 gears with a pumpkin swap, Carter's website has a tech tip on this. Randy's ring & pinion sells 3.90 gears, but you have to swap out pumpkins, and spend big bucks for the gears. Swapping out the entire differential is another possibility, but they are 3.5 inches wider, causing more problems. I am looking into a differential swap with newer wheels, which have more setback, but it could take a while. I have a lot on my plate right now.

I can't even see my plate anymore Fred-T :p
Best solution for now seems to be just driving slow the way these trucks were meant to. Thanks again. --Oh yeah, could you do an entire rear end swap with a half to axle with 4.11:1 gears?

maybe with a 55, but prior to that the driveline is closed.

Tony,

The 3/4 AD's had a closed shaft to about the back of the cab and an open shaft to the rear. Hence, you can swap "punkins" all the way up into the late 60's (maybe thru '72) with a '50 and up 3/4.
It's an open rear.

OOPS!! now that I read the post above yours, I understand. You probably knew about the 3/4's. Sorry.