Stovebolt.com Forums The Parking Lot '60-'66 Trucks 66 c10 transmission

Hi everyone. I have a 66 chevy c10 with a 3 speed trans on the floor. I'm considering in replacing it with a new trans.would a th350 turbo trans would make a nice conversion? Appreciate your thoughts and answers

There are many transmissions options and it all depends on what you want and what your skills and/or funds are. If you currently have a 3 speed trans it started out with a column shifter. The floor shifter has been added somewhere in it's life.
Your current configuration has the rear mounts located between the bellhousing and the crossmember. Any auto trans that you choose would have a mount near the rear of the trans. You would likely need to procure an aftermarket rear crossmember. You will need a flexplate, starter, either a new radiator with a built in trans cooler or a remote cooler and lines. Also, some sort of shift mechanism, and driveshaft modifications. Most current conversions involve a more modern overdrive trans such as a 700R4 or 2004R. However, there is nothing wrong with a 350 trans, it's just not an overdrive.
Fred

early classic enterprises has all you're looking for. Mounts, radiators, etc. you can build a truck from their catalog. They're in California also. There's a member named 4-5-6chevytrucks I think that has a shop dedicated to these rides also. Maybe he can help.

Thanks for your help guys!well much needed advice

It is much easier to put in a different manual trans. then an automatic. You have to remove the major crossmember under the bell housing to put in an automatic. The 4 speed trans from a car is good. It has closer ratios then the 3 speed or the old truck 4 speed. A 5 speed manual with o-drive is a good choice as it gives a much better high way cruiseing gear.

To determine which transmission would work best for your truck you must 1st consider what the rear differential gear ratio is, the rear tire diameter is and how the truck will be used.

The problem with a car manual transmission is the first gear ratio isn't typically correct for getting a heavy load moving. The granny gear these trucks came with were there for a reason.

But if you are seldom pulling a load, or hauling a heavy load, a passenger car manual transmission will work as Wrenchbender describes above.

I have a Muncie 4 speed M-21 passenger car transmission in my truck, a 3.73 rear gear and 33" dia. rear tires. It is great on the highway, but you have to slip the clutch a bit to get it moving. Ideally a steeper rear gear (like a 4.11) would be ideal, used with an overdrive transmission, also as Wrenchbender discussed. This gives you a good overall gear ratio for pulling / hauling loads, but good highway mpg also.

This gear ratio calculator will help in sorting out what will work best: http://www.4lo.com/calc/geartable.php

Another thing to consider is an overdrive unit for your existing transmission.

Hope that helps

John

Replaced my 3 speed with a turbo 350.Fairly simple,used junkyard parts,well worth it if you want a automatic.Overdrive would be nice,but would take a lot of driving to offset the cost of one.