[MUSLCAH]

Got 2 questions..(1) what year bell housing # 9770091.... question (2) on a 1964 Grand Prix 389 4 barrel ...what size bolts are used to bolt the bell housing to the motor ? Thanks for any input

[Stuart]

I take it that's a casting number and not a part number? Per McCarthy's book, a casting number starting with 9770 corresponds to roughly late 1962. Does it have provisions for a bellhousing mounted starter?

[MUSLCAH]

Yes

[johnta1]

I show it as a 1963?

Look like this?

[MUSLCAH]

Yes it does....Question ...see those bolts that hold the tranny to the bell......is that the same size bolt that holds the bell housing to the motor....or are the bolts that hold the bell housing to the motor a smaller size ? Thanks

[johnta1]

are the bolts that hold the bell housing to the motor a smaller size ?

On the newer bellhousings the bolts are 3/8",would think this one is the same?

The ones for the tranny to bellhousing is bigger diameter.

[pfilean]

My 1966 parts book says 9770090 is a 63 exc. SD. So is the 9770091 the SD version? Don't know - not in the parts book. Parts book also says bolts for housing ass'y to block are 7/16-14 x 1 3/8 for 61-62 P8 and T4. For 64-66 all they are 3/8-16 x 1 1/4. 63 not listed - but my guess would be 3/8-16. And then I can't find the listing for trans to bell housing.
That parts book is nice when the numbers are in it but then there are often some gaps.

[Stuart]

I think the 9770091 is a casting number, not the part number. However, the part number (I think) is typically close to the casting number, so the 9770090 you see in your parts book is probably correct.

[gtoguys]

I just put my 63 389 back in and the bell housing bolts are 7/16" x 14. It is an automatic.

[johnta1]

Thanks for the info gtoguys and pfilean.



I would think the 64 engine the OP has would be 3/8" bolt size though?

I'm not up on the bolt sizes though.
Knew the older ones had the bigger bolts, but thought by 64 they went to 3/8"

[tom s]

For some reason I thought the 64 used 3/8 on the center top 2 and 7/16 on the others.Been awhile since I looked at one.I know Brad at Fabcraft would know forsure.Tom

[MUSLCAH]

I did talk to Dave at Fabcraft today....and the bell I have ...is a late 63. Have to send him my eng block #... to see if that 63 bell will work on the 64. They were talking slight differences in length in the eng block and bell housing....that would screw up the alignment of the clutch linkage...time will tell ,if I have to chase another bell. Been a Chevy guy for all of my adult life....but thought I'd slip to the dark side....oh my...things don't interchange like the chevys.

[Goatracer1]

1964 Blocks use a 3/8 bolt. Wouldn't matter if auto or manual.

[johnta1]

I'd try to get a newer bellhousing to use.
There were millions more of those.



The one you have may be better for someone with the older blocks.

Maybe someone would do a swap?

[tom s]

John,if he does that he will need a diff flywheel also!Tom

[johnta1]

Isn't 1964 and up interchangeable?
His block is 1964 I believe?

[tom s]

If he uses a bell for a block mounted starter he has to have Flywheel to work with it.The ring gear when using the bell starter is in a diff position

[tom s]

And the linkage won't work as designed

[johnta1]

Thanks, Tom for the info.

[MUSLCAH]

This is getting ugly.....getting the wrong parts from known old Pontiac guys...paying shipping twice to return items..."the high cost of an education"