what the ? i got a new oil sender for the 351 and before it was showing 0 -10 and i picked a new one up for a 86 f150 w/ 5.8Lfrom auto zone and the thing reads 80 psi ! and never moves .. i did notice when i removed the old one it had a reducer
from the pressure stem to the old sending unit , new one is like 1/2" NPT and the reducer was like 3/8" npt ... is there a special kind or something for boats ? new one on me