4 bolt main oil cooler plugs

[Jeff M.]

In a 512 block or for that fact any 4 bolt block, I know that the block was drilled and tapped for the external oil cooler. The paragon book shows a 3/8" fitting for the oil pressure gauge for the 2 bolt (ls5) and a 1/2" for the 4 bolt (LS6). I assume that the oil pressure gauge was still installed in the same hole, just drilled out to accept the 1/2" NPT fitting . Were the other 2 holes to the left and right tapped and plugged? (I think so) or just one. A picture would answer all of my questions. My block is a 4 bolt main,but does not have the external oil cooler machining, and as it is out being rebuilt, I will make the change externally.I looked thru all of the archives back to 2003 and still do not have a clear picture of the correct configuration

[John H.]

Re: 4 bolt main oil cooler plugs

Jeff -

Photo below of a machined 4-bolt block.

[Joe L.]

Re: 4 bolt main oil cooler plugs

Jeff -

Photo below of a machined 4-bolt block.

John and Jeff-----


...and the "fitting" to the right side in the photo was not plugged because it's not a fitting, at all. I believe it's a clutch cross shaft ball stud mounting point for some application

[John H.]

Re: 4 bolt main oil cooler plugs

John and Jeff-----


...and the "fitting" to the right side in the photo was not plugged because it's not a fitting, at all. I believe it's a clutch cross shaft ball stud mounting point for some application

Joe -

That's correct - it's a threaded blind hole, and is used for the clutch cross shaft stud on Camaros (maybe others as well).

[Jeff M.]

Re: 4 bolt main oil cooler plugs

John, great picture gives me what i need. What size is the hole on the left that is plugged

[Joel F.]

Re: 4 bolt main oil cooler plugs

1/2" - 14 NPT for the forward hole, and 3/4" -14 NPT for the rear hole.