[Coldairxc]

Is there any difference between the ISB 3.9 to the 4BT in how the transmission is spaced? Im trying to adapt a early Gm NV4500 to a ISB 3.9 Talked to the guys at quick draw they say you cant use the early NV4500 with there kit.
They do have a kit that works with the early Nv4500 for the B series. But says the 4BT wont work with the ISB 3.9 Im so confused.

 

[edpruss]

Early 4500’s have GM bolt pattern, input shaft.

Ed in CO

 

[Coldairxc]

Do you happen to know whats the difference between the ISB and 4BT transmission mounting? Saying if they are SAE3 bolt pattern?

 

[edpruss]

SAE #2 and #3 might be available.

Ed in CO

 

[Coldairxc]

SAE #2 and #3 might be available.

Ed in CO

Ok should have been clearer. So this ISB is a SAE 3 bolt pattern, the 4bt bell housing adapter is also a SAE 3 pattern.