Count the number of threaded holes holding the bellhousing to the block. Be aware there are also a couple of non threaded holes where the alignment dowels go.

Its been a few years but the 5 bolts almost always had an aluminum water pump



6-bolt above 2 on lower right                                                                
                                                                           5-bolt lower 1 on lower right

Last edited by bulletbirdman (5/12/2017 1:20 AM)

Ah the missing bolt would be on the same side as the starter. I can't seem to see the bolts from the top, is it easier to seem them if I jack the car up? Only asking cause if I got a 5 bolt block I'll probably look for a 5.0/5spd combo for sale vs trying to sort out the heating issues on my current motor.  I might also let the car languish in the garage for another year.

If memory serves, the 5 bolt block was used with the 221, then the 260, and first year 289.  From late 65 on, they were 6 bolt blocks.  I had a 65 Falcon 289 4 spd (alum Borg Warner T-10 from the factory) I raced in the early 70's with a 5 bolt block.  When I bought a 66 Merc Cyclone with a 289 4 spd (small top loader), I tried using the other bell housing and the bolt difference became obvious.