what size bolts for tranny to engine block?

[crosby]

I have an 87 K20 (which happens to have an early 70's frame and axles), and I'm sticking in a fuel injected 350, mating to a TH400. I don't have the bolts that go through the bellhousing into the block, and want to be sure they're not too long (or too short). Anybody know how long they are supposed to be? It's not 100% where it needs to be, so I plan on using the bolts to finish lining everything up. The guide pins are almost in place, but there's about 1/4 to 1/2 inch of space between the block and the bellhousing right now. I still have to bolt up the torque converter and flexplate too, anybody know what size and length bolts I need for that? Should I use split lockwashers on the flexplate/torque converter? Thanks very much for any help you guys can provide!

[86 GMG]

i believe 2 1/2 should work but put a smaller diameter bolt through trans and in to the block hole see how deep it goes and go from there

torque bolts no washer just raw balls and torque and thread lock

[crosby]

That's a good idea, thank you.. off to the hardware store

[MylilBowTie]

It wouldnt hurt to use washers. I would if it was mine.

[plumbcut]

I agree w/ mylilbowtie.... I use lock washers on my bellhousing bolts.. keeps from scarring up the aluminum trans, too...

[bigblock73]

I just bought new bolts for my setup, and IIRC, I purchased 1 1/2 or 1 3/4" bolts. I believe they are also 3/8" threads too. Don't take this as gosphel, I have a bad memory...but I am pretty sure about the length.