61 bellhousing identification

[VetteVirgin]

While searching the archive I found a post that stated that only two bellhousings were made with the boss for the z-bar bracket.
Since my bellhousing has the boss and appears to be aluminum (according to my magnet), then can I safely assume that I actually have a correct "553" bellhousing?

DT

 

[JohnZ]

If it's aluminum and has the tapped holes for the Z-bar bracket, it's either a 553 or a 591; you can't see the casting number unless you pull the transmission back. The only difference between the two is the size of the hole for the clutch fork. The 553, used in '61-'62, has the larger opening.

 

[VetteVirgin]

Thanks John! I just googled 591 and found one of your posts on the "other" forum on the topic. Since the 591 was a 1 year only use I'm feeling pretty comfortable that I have a 553. I guess I'll know for sure when I replace the throwout bearing and clutch fork!

DT