I have a 1974 Pantera which I've updated the cooling system using the example set in sticky #3 from this forum. Fluidyne Pantera radiator with dual sucker fans, condenser in front. Weiand waterpump, not modified, with a water pump reduction pulley. Above 90 degrees ambient the 260 temp guage, with Pantera-Electronics compensator, appears to peg high at speed, as soon as it comes back to a normal cruise speed or idle it will read about 192. To me this indicates an air pocket.
I'm purging the system again this morning with the real elevated, 13psi cap, ran it up to about 110 degrees and shut it down, purged the air and got minor overflow out the tube. Fluid topped off before running. Topped off again and ran until cooling fans turned on and shut down, purged and overflow was slightly more tha 1 quart. Took temp reading on coolant and it was 150 degrees. Ran test a 2nd time, holding rpm at 2000 for 3 minutes, purged and overflow close to 1 gallon, temp reading 190 degrees. Also in the the past I have pulled the temp sending unit and water poured out. I'm not familiar if that water coming out would be before or after the thermostat..
I'm stumped as 150 would not be opening the kool-flow thermostat it seems. Perhaps the waterpump pulley should be returned to oem?
I'm open to suggestions. FYI, I've tried in the past to loosen the water ports in the block with no luck, they are the square head plug not the socket head cap screw.