Block and Tranny assistance

I'm helping out a guy with a 67 mustang and had a couple of questions.

1. I'm trying to figure out what motor is in it. I've pulled the casting numbers off the intake manifold and exhaust manifold.
The intake manifold - D5TE-9425-TA
The exhaust manifold (pass side) - C5SE-9430-C

When I search for those numbers just through google, both show that they are a 390 part. Is it safe to assume that it's a 390 motor? I haven't found anything saying parts were interchangeable, but thought I'd check.

I've tried finding the block code but have been unsuccessful in finding it. The only thing I've found is the date code, which reads 3K18. Which based on my findings is either a 63 or 73 block casted on Oct 18th.

2. Second issue is it appears half the bell housing is missing. I've attached a picture showing what I see. Can anyone tell by the picture what's needed to cover that up?

I appreciate any info anyone has to offer. Next step is trying to figure out what tranny is in the car.

Excellent, really appreciate the info. Any pics or description of what that counter balance might look like? Or where on the flywheel it's located. I'm going to try and crank the car over to look at it. Also going to count the teeth on the flywheel.

Third issue now is the starter isn't engaging the flywheel. It just spins. I don't hear it make contact at all. Might need to read up on shimming the starter to see if that might help.

Thanks fellas. Looks like I'll have some looking to do this weekend.

Thanks again