I got a 79 TH-350 that came out of a 1 ton chevy van going in my 88 camaro. Im gonna get the TCI Breakaway converter for it, but there's 3 different ones listed.

1}TH-350/400 dual bolt battern TCI-240900
2}TH-350/400 small bolt pattern TCI-241300
3}TH-350/400 large bolt pattern TCI-241400

How do I tell which one I need?
Can I measure something somehow?
I have the trans and the stock converter but I dont have the flywheel. (I have a flywheel that I am putting in the car, but not the one that was originally bolted to the van that I got the trans from)