Ok what size thread is weird after or what adapter do I need pour the oil temperature / oil pressure gauge Port right above the oil Filter I cannot find the correct one.

 

For an 80,s 350

 

1/8" pipe AKA 1/8 NPT.

 

Thanks so much this has been o pissing me off for a while

 

Isn't the port above the filter 1/4" NPT;
it is larger than the 1/8" NPT port at the rear of the intake

 

^^^This^^^

It's actually the plug that blocks the end of a drilled passage about ½" in diameter, that goes from the oil filter over to the vertical passage up the back of the block

 

??? Im confused

 

Typically there are two (sometimes three) places where you can screw in an oil pressure sending switch.

Location #1 is at the back of the block on the driver's side of the distributor. IIRC, some of the early blocks don't have a hole here. Looks like you swapped in a V8 so we don't know the pedigree of what's under your hood.

Location #2 is above the oil filter. This is the location you're referring to in your original post, yes? You might see two holes at this location. The bottom one is for the sender. The top one of for the ball for the clutch equalizer.

Location #3 is at the front of the block on the passenger side in front of the intake manifold. Some blocks will not have a pressure tap here. If the block does there will be a small 1/8-NPT threaded plug blocking this off. This hole is generally not used.

The threaded holes at all these locations are either 1/8-NPT or 1/4-NPT.

Depending on what pressure sender you have and where you want to mount it, you may or may not need to buy either a bushing that adapts a 1/8-NPT to 1/4-NPT or a bushing that adapts a 1/4-NPT to 1/8-NPT.

Also note that NPT threads are tapered. Avoid over tightening the sender. They don't have to be reefed on. Use liquid Teflon sealer on the sender threads if it doesn't have sealer on them out of the box. Avoid Teflon tape.

 

Thanks guys it was 1/8 thread