4406bbl thanks for checking on the radiator inlet and outlet port sizes.
I did confirm the gage is accurate with a second gage and laser temp gun. So I am going to try less timing, going from 15 initial to 8 initial and a step richer jetting, to see if temp drops. Motor is stock bore motor home, at 8:1 comp so it probably doesn't need all that ignition. If this does nothing, then rad will get pulled and tested, its a used unit I have had for near 20 years hanging around in my parts collection.
Mike
That is correct. My 69 “053” big block radiator has 1.5” inch upper and 1.75” inch lower inlets. Later today I can measure the small block radiators I have.
So if the radiator inlets are right, I’d make sure the pulley ratio is correct for the number of water pump impellers. Also there was a comment about aftermarket aluminum water pump housings. If you have one of those I try going back to the factory cast iron to eleminate that question.
