dual bolt pattern Questions..

[GMNorway]

How do i identify dual bolt patern on my transmission?
i suspect my 81 Calaise has one.. I suspect it's a th350 unicase but not shure.
The top of the bellhouse looks similar to the one in the pic.
I can feel the the extra hole for the chevy patern..
The pan looks like the th350 type, and it has the vacum modulator in the back of the case. ( not shure if all trannys has that)

Sombody who has pics or any tips to how i can id it !!??

 

[GMNorway]

 

[Bonnewagon]

This may help. Plus this link-http://www.transmissioncenter.net/PanShapes.htm

 

[pontiacgp]

best way is you get under the car and take a look at the bellhousing

 

[GMNorway]

Ok, thanx. I wil take a look under the car tomorow 🙂

 

[GMNorway]

It's a dual patern TH350C lock up Trans for sure 🙂10 bolt holes, and It has the electric wiring for the lock up on the drivers side.
i suspect this is rare combo, TH350C and a 260 V8?! :?
The rear end is 10bolt 7.5 inch.. Not sure about the ratio..

 

[Blake442]

The dual-pattern TH-350 was fairly common for a few years in the early '80s...

My Cutlass wagon had one behind it's original 3.8 V6.

 

[GMNorway]

Ok.. 🙂
Did the 250C come with Dual-patern and electronically controlled lock-up torque converter?
These trannys look the same dont they?

 

[pontiacgp]

 

[Bonnewagon]

Yeah, my 83' Bonneville wagon w/3.8 had that trans too. I gave it to a demo derby driver.