then that means your trans is an A745 ......which is typical for 66 .....you need a later A230 which has a mounting plate for the floor bcoz floor shift 3 speeds became optional later.
that plus the 230 is a lot tougher ....your 745 is a top loader and the 230 is a side loader and looks like a mini 833.
a 230 is beefy .......i can almost bench press a 745 it light as a feather and made for light duty.
