trying to install some gages on my 4.3 v6


1. is the 9/16 bolt (plug) directly above where the oil filter screws on a oil passage suitable for a mechanical gage port?

2. is the 9/16 bolt (plug) on the back of the engine by the distributer but down by where the bell housing bolts on. (this is close to the stock oil sender by the mainifold) a water passage?

For some strange reason I believe on the 350 in my car I put the oil gauge tube fitting in the one by the distributor My cars not here so I can't confirm But then again I'm :smokin:
I'll let you know after work tomorrow if no else gives you the anwser

I think you have them reversed. This is strictly from memory, but the port just behind/below the distributor for the oil pressure, and the one on the side of the block and above the oil filter is the temp. gauge sending unit port.

I'll also verify tonight - but I'm pretty sure.

My oil sender is behind, lower and a bit to the driver side of the distributer. the sender itself is pretty close to touching the distributer when installed.

the oil sender is nearest the distributor (tapped for 1/8" NPT)
the water sendor is on the side of the block above the oil
filter hole. (also tapped 1/8" NPT) I believe...

I would have to say they are both passages for oil. Atleast on many of the big blocks I've had, the one above the filter is for oil also.

The one behind the dist on the block is for oil. I always thought the temp was in the side of the head.

On my 350 (out of an '87 K5), the oil gauge sender is in the driver's side of the block, near the oil filter, kind of behind/under the headers. There is also an oil sender near the base of the distributor (the one for the fuel pump relay bypass).

Pete

Every SBC water temp sender I have ever seen has been in one of two places.

1. (and most common for pre-87 factory stuff) is in the side of the head between #1 and #3 (or #6 and #8) spark plugs. The hole will be 1/2 NPT (older) or 3/8 NPT (newer)

2. Somewhere in the intake manifold.

The 9/16 hex head plug is the drain plug for the block coolant. Not oil. There is one on the other side of the block as well. It allows you to drain the coolant from the entire block before you pull off the heads, eliminating coolant in the oil pan and pistons.