The mystery fitting is a constant dual vacuum source. It's a little unusual to be cast out on the opposite side of the head but it's par for the course on this odd ball integrated head 2bbl 250.....
Discovered why someone applied nearly a full tube of gasket sealer on the thermostat housing. It seems the upper housing was correct but not a correct match for the bolt on lower housing. The upper half has offset bolt holes and the lower half has in-line bolt holes which just so happens to match the upper housing on my freshly rebuilt 54 235. Not only were the housings not matched up correctly but the thermostat wasn't centered in the upper half. How it didn't leak is amazing. It's a testament to powers of permatex...... So I bolted up the 54 235's upper housing and it worked perfectly. Had to find a new upper radiator house with differing sized ends....
PicPic 2Removed those smog pipes and plugged the exhaust holes with M18x1.5 bolts.
PicInstalled the 1/8NPT fan switch in the head and installed the new temp gauge probe in the lower thermostat housing. Both worked pretty good. The fan cut on at 200 and dropped but the temp didn't drop below 185 so it stayed running. It avg about 190 degees during testing. Removed the electric oil pressure sender and installed a new copper line for the ne woil pressure gauge.
Pic 1Pic 2Pic 3Got the gauges installed. Oil pressure cold was 35 at idle, hot was 20 at idle. Temp avg'ed 190 degrees.
Volts = 13.5.
PicWith all that said and done, I'm still chasing either an elusive vacuum leak or too lean condition. I finally got a double D adjustment tool to see if I can make the idle/low speed mixture richer to see if it makes any difference and the danged bit dropped out of the flex tool and found it's way down in a void somewhere between the intake and exhaust manifolds from which there is no return. Perhaps I'll try to retrieve it once it's cooled off or just go pick up another.
