1110985 flat surface opposite tach threads has a hole

[Brian B.]

I have 3 distributors all claiming to be for a 340 hp 1962 car. on the semi-circular flat surface on the opposite side of where the tach cable threads on , I
have 3 situations. One is undisturbed and has 75 cast on the side on the shaft. One has a 1/8" unthreaded hole drilled in the middle of the flat surface ,it has a casting number of 40.
the last one has a bolt with a lock nut screwed in to it. the bolt head is 1/2" and the casting number is 51. Are any of these correct for a march 62 car. The dates on the
aluminum tags are good. Maybe someone out there can enlighten me as to why the holes might be there and if the casting numbers mean anything. I am resigned to the fact
that I may have been "Bubba'd" and / or"Ebayed" ...AGAIN
thanks.. Brian

[William C.]

Re: 1110985 flat surface opposite tach threads has a hole

The "no Hole" version is correct. The small hole was added at the time when the plastic thrust washer was introduced, I believe in the shark era. Bolt with locknut is a "Bubba" repair. A little deeper dive into the parts book indicates the button was introduced in 68-69 for the 427 engine, '70 for the LT-1, and '71 for all applications.

[Brian B.]

Re: 1110985 flat surface opposite tach threads has a hole

Thanks Bill, I looked closely at the I.D bands and only the "no hole" one doesn't look like it has ever been disturbed. I have been researching for weeks to no avail, didn't want to ask a "stupid" question on the board. next time I'll
ask first and save myself some money.