I recently bought a 1959 Lark VIII that a previous owner installed an oil pressure gauge in and that its readings concern me. When cold it indicates 20-25psi idling but quickly falls to about 5psi when warmed up, I should add that at no time has the oil light come on and it does work. Down the road at 55 warm is 20psi. I was told by the owner who is my neighbor and trustworthy that the engine was completely rebuilt about 10 years ago but has had little use in that time with less than 5k miles accumulated. My first thought was those pressures seemed low but perhaps it was a defective gauge, which I plan on replacing. But if those are the actual pressures my next thought was the oil pump. In doing some searching I find that only the oil pump gears are available and not a complete pump assembly. Does anyone know where I can buy a complete new pump? Also any other thoughts are appreciated, thank you.