The Stovebolt Site Forums The Shop Area Engine Shop Tranny woes

Ive just installed a 1968 Muncie M20 into my 65 chevy. They had trouble installing it since they couldn't find a bellhousing that would fit the 292. They finally got it in feels great but it wont go above 55 mph. What do I do to run at highway speeds?

Nothing wrong with the tranny - it's more the rear axle which is the limiting factor. The final drive ratio of the tranny is 1:1, unless you had a tranny with an overdrive.

Rear axle and "pumpkin" swaps are common, search the archives or vendors for some ideas...

-Boyo

I was hoping to install a new rear end. Something along the lines of a 80's 4x4, I still want to keep it six lug. Do you think this is a good idea to install it, recommend anything?

Do you know what your gear ratio is? It will help quite a bit in deciding what to do.

BIGGY,

I have a 66 stepside with a 230 engine. I can still run the highways very easy at 60 mph, with the stock drivetrain (3 speed column-shift non-overdrive transmission and 3.73 rear gears). I've driven trips of 50-75 miles on the interstate at 65-70 without any problems, though this is really pushing the limits of the inline 6. At 60 I'm turning about 2850 rpms.

You must be running either a 4.11 or 4.56 gears. Those are horrible gears for cruising. Find a 3.73 or 3.55 chunk and change it out. If you have a "Dana" rear end then 4.11 may be as high as you can go. Then your only solution is an overdrive tranny.

I'm finishing up my 292 project and I'm mating it with a GM 4-speed overdrive transmission. So I should cruise at 70 on the interstate.

Even with 4.56 gears he should be able to run 70, unless he has tiny tires. I'd guess that something is wrong.

If he did get it up to 70 he certainly won't be cruising. Unless he had 55 inch tires

Well I do still have the factory skinny tires not in bad shape. But in the street I have to go into 4th gear and its in somewhat high RPM. I dont have overdrive, but the change was important since the 3speed on the column bothered me. I'm 6'5 and at 2nd gear it would hit my knee. How would I find my rear end gears?

There are a lot of GM 12-bolt rear ends that will have either 3.73 or 3.08 gears.You should be able to locate one out of a 2wheel drive truck that will bolt right in.(6-lug even )