Oil Sending unit

I have a 1955 F250 truck, 239 engine, stock 6 volt oil gauge with voltage reducer (converted over to 12 volts).

Oil pressure gauge reads 5 lbs., mechanical gauge reads 40 lbs at idle.

What electric oil sending unit can I buy at the local parts store to keep my stock oil gauge? OR ???

Thank you for all responses.

Name change from Shrek to THE HULK! LOL