I bought a LO5 (police version) recently which Im going carb on so I dont need the knock sensor. My question is does the hole have to be plugged? I cannot find a plug for the knock sensor or oil pressure sensor anywhere....Everyone told me its 1/4inch PT but its not. I know I have to plug the Oil pressure hole but what about the knock sensor?

 

Yes they must all be plugged.

The knock sensor hole has been on every SBC motor since 1955. It was called the pass side coolant drain before they started putting the knock sensor in it.

Some of those blocks have an additional hole above the drain plug hole that lit a "coolant change" indicator. That one is some metric size, do a search on this board for the word "contamination", you should be able to find it.

There are 2 commonly used oil pressure gauge ports on a SBC; th eone on top of the block behind the intake is 1/8" pipe, the one right above the oil filter is 1/4" pipe.

 

i bought a 1/4'' pipe thread plug and they wouldnt fit. according to our computer at work the sensors are 1/4'' by 18 thread/

 

Just pull the wire off and leave it in. With the wire off its just a big plug.