I have a 1949 3100 with a 1954 235 in it no oil filter. Normal Oil Pressure runs pegged at 30. Last nite I drove a bout 20 mile round trip to pick up my daughter at soccer practice, along the way the oil pressure needle would drop to 0 then a few seconds later, peg back at 30. Any ideas?

Suppose ther is some crap in the oil pressure gauge line?

Thanks!