T56 for Muncie question, help

Hello all, thank you for this place to help me understand better. I appologize if I have posted this in the wrong place.

I have a 66 Lemans with a 350 Pontiac and Muncie close ratio trans. I dislike my gearing very much and would like to replace it with a T56 6 speed. I see many for sale but how do I know which ones would fit my engine or bell housing? Thank you for any help in advance.

here are the numbers from my Muncie-

3925660
US Patent 3088336
General Motors Corp.

P8A09
3857846m

Thanks again!
Murunga

I don't think any T56 will fit your current bellhousing but I may be wrong. You have several options. You can buy a Lakewood housing, or you could use a regular chevy bellhousing like from a late model camaro and adapt it for your pontiac engine bolt pattern.

Your older 4-speed probably has a 10 spline input, with the T56 has a 26 spline input. A new clutch will need to be used. You'll also have to decide if you're going to use the newer hydraulic clutch (pretty easy to adapt) or retain the mechanical clutch and adapt it to the newer clutch/tranny.

There are tons of sites out there with thousands of these swaps already done. I suggest a google for "t56 swap". You'll find them in A/G bodies, F bodies, S10s, the works.

But, to get you started on the right path... you are looking for a T56 that originally came from a GM product. That way the clutch, input shaft, bellhousing pattern, and output shaft are GM pieces that will be either a direct fit or easy to adapt.