I am looking at what goes where on my truck and I see holes on the lower front face of my clutch housing(1950 Chevy 3100 1/2 ton with 216). There are 2 on each side. What gets bolted into these holes?

Also, on the drivers side there is a 1 1/2" hole. Does this just stay open, or is there a plug for it?

Dumb questions, but I have looked at the manuals and I could not find my answer. You guys are a lot of help. Thanks, Jerry