GM bolt sizes

[19sixtynine]

So i'm putting the motor in this weekend and wanting to replace a lot of missing/damaged bolts but don't know the correct sizes. bolts such as water pump to block, bellhousing, crossmember thru engine mount.....i'd like to just go to a local bolt/screw dealer to buy them all but all I know is that they are grade 8. Does anyone know of a good resource that can tell me bolt size and thread count for GM bolts?



FWIW it's a 79 GMC 454 going into a 1969 Camaro with a TH400 and i've got all the right big block mounts on the frame and engine.

Thanks all,

Robert

[moreHP]

Water pump to block bolts should be 3/8-16 which is 3/8 course (very common) I dont know where you are in relation to a Lowes store but the local one to me has a really great selection of grade 8 and stainless hardware in all the common sizes. As far as length goes you can measure the thickness of the water pump flange + any bracket that may attach there and then add 1/2" for going into the block. Mating up the trans should be 3/8" course too.

[19sixtynine]

Awesome, there's a Lowe's not too far from me, thanks so much for your help Bob!

robert

[6'9"Witha69]

What isn't 3/8-16 on a 1st gen?? *sarcasm*

[novaderrik]

every bolt listed is a 3/8-16, but in a few different lengths.
i know the motor mount to engine bolts are 3/4" long grade 8- every other bolt will be grade 5- the crossmember to frame mounts should be about an inch or so, the bellhousing bolts about 1.5" long, and the water pump bolts around 2" long.