What size is the aluminum bell housing

[Chlngrcrzy]

Are all big block aluminum bell housings 10.5"  or can some of them be 11"?
I am trying to order the correct Z-bar and service kits for it and the clutch. I am pretty sure mine is an 10.5", but i want to be certain. Mine is aluminum.

[73EStroker]

I believe your flywheel determines bh size - ie 130 tooth you need a 10-1/2" bh and 143 tooth you need a 11" bh. If you use 11" bell on small flywheel the starter won't engage properly. Most of the new aftermarket units are aluminum. Originals came in both and to determine what you have you need something like Govier books or simply post the casting number and I will check my books for you.

[Chryco Psycho]

In My experience alum are 130 tooth cast iron are 143 tooth

[Chlngrcrzy]

In My experience alum are 130 tooth cast iron are 143 tooth

Sweet. Thanks. Mine is a 130 tooth. I thought it was a 10.5"

[Chryco Psycho]

The 10.5 is the same bolt pattern as the 10.95 clutch so I always use the larger clutch , it has more surface area & from a leverage standpoint .5" is a lot more