I am putting a 454 BBC into my car... but I have a quick question about these three threaded holes near the oil filter. I tried to circle them in yellow. What do they do/hook up to? And where can I put my gauge sender? How about an oil cooler? Thanks!

i think the one right above the filter to the left can be used for a oil pressure switch, (mechanical in my case) i dont know about the rest. on my 454 all of the holes are plugged except the ones that had things in them. also i have a question for anyone else who might know, do these need to be removed before hottanking the block? sorry dont mean to hijack

The other two are for mounting things to, such as the ball for a clutch z-link.

wow, feel like an idiot. i just realized you didnt have the one i mentioned circled. sorry

The large one is a pressure tap. Normally used for a pressure sensor. Can be used for an oil pressure source for turbo's etc. You can use it to feed an oil accumulator also. Plug it if it's not required.

The smaller hole above the filter is just a threaded hole. It's for mounting a pivot ball for mechanical clutch linkage.

The small one in the side of the block should go into a coolant gallery but may also be a blind hole. A temperature sensor or knock sensor would normally go there. You can put a drain tap in there to help drain the block but it's above the frost plugs so it wouldn't drain very much.

Thanks Stephen! That cleared up a lot and was a big help.