I know it's a different critter, but my HM 351 always runs cool on the gauge. I asked about solutions several times over the years on this forum, and always got the same answer... just run it, raw-water cooled Fords always show low temps. I have been running this way for eleven years with zero ill effects...
Just to make myself feel better, I shoot the oil filter with a temp gun on occasion. Oil temps are good and warm after a hard run, so I know I'm not running too cold...
1970 18 2+3 Hull #18-355 H/M 351W Volvo 250
07 Cayman IT IS BACK! - '13 Abarth Cabrio
PRESERVE, DON'T RESTORE