Starter Housing Identification

[JSB55]

These two starter housings are nearly identical, and apparently interchangeable, but which is correct?

The one on the right, with the relief passage at about 4 o'clock was on the Delco Remy starter on my 65 FL. On the left is a spare from my parts collection.

Clearly I can use either, but which is correct for a Delco Remy starter on a 65?

20241121_133203.jpg

Any info appreciated!

John

[vph-d]

The housing on the left is correct for a 65, the slot was addressed in an August 8 1966 Service Bulletin. I'd use the one on the right.
vph-d

[JSB55]

Interesting! Thank you vph-d!
I actually found that service bulletin. Passages intended to drain away any accumulated water.