What size bolt (and washer) is used fasten the frame to motor mount? I can't seem to find this specified in the Firebird manual. Also, do you know what size bolts and washers are used to mount the transmission mount to the crossmember?

I just got a set and they were

3/8-16 x 1 1/8", 9/16" Hex, .65" Split, "SEMS over T", Black Phos. 2 pk

Where can I buy these?

I might of misunderstood you. Are you referring to the single bolt that that attaches the fame mount to the engine mount? If so, that is a 1/2 x 20 in fine thread.

About any bolt that size should work. I have not seen any specific bolts listed for it. I did just buy a couple from franks pontiac.

Yes, the single bolt that attaches the frame mount to the engine mount. Thanks for your help.

How long are are your 1/2 X 20 bolts? I purchased 1 inch bolts. They had 1-1/4 bolts so I could go back for these. Thanks for the help on this so far.

Mine is 1 1/8 but there is only about 7/8 thread. You should be fine.

I just checked my bolt with the new engine mount and the new engine mount threads are not as deep as the engine mount I took off. The way the original bolt is made I'm loosing to many threads. I will have to get a regular bolt too.

Just picked up a 1/2 x20 1" and it bottom out too. Might have to try the 3/4 or add another washer.