knockbill

after reading teh bellhousing/starter thread, and looking at all the pics, i just remembered a question i had about bellhousing to engine mounting holes, small blocks in general,, but i'm interested mainly in 283's...

i have a 67 block, was out of an automatic car,,, it doesn't have teh top center hole drilled and tapped,,, anyone know when that was changed? was it just for automatic applications, or did chevy stop drilling/tapping all blocks on a certain date?
thanks....

JohnZ

I don't recall when/if that changed, but it didn't have anything to do with manual vs. automatic transmissions; the Machining Department at the engine plant had no clue about what transmission any block was going to use - they were all machined the same at any one point in time.

rongold

A lot of bell housings also do not have that top center hole drilled. I bought my 621 bell housing brand new in 1989, and the top hole is not drilled for a bolt.

knockbill

thanks for the reply,,,
well, it did end at some point,,, the manual vs. auto, makes sense...

i guess since they stopped drilling/tapping it, its not necessary...

knockbill

[QUOTE=rongold;1580803930]A lot of bell housings also do not have that top center hole drilled.


i wonder if it happened at the same time???

Kerrmudgeon

John, if that's true, why does my 64 block not have the left side holes drilled and tapped on this block, while the right side does. I found that out when I was going to bolt my front mount 56 mounts to it.

knockbill

was something attached at the right side, old front mounts, in some 64 small block application?

JohnZ

I don't know - I've only seen a few blocks with the bosses not machined on one side; that spotface/drill/tap station in the transfer line must not have cycled, and they just let it go. The right side holes weren't used for anything after 1957 (until 1969), so it didn't matter.