jn01

The oil pressure gauge in my 74 small block, hot or cold, typically reads a smooth 40 to 50psi. However, over the past few months the needle jumps erratically back and forth in the gauge. I have no idea what the oil pressure really is.
Any ideas as to what is going on?

Thanks

427basketcase

Is it mechanical or electric? If electric then you have a loose ground, or bad sending unit. If mechanical then check the line for kinks, or other obstructions.
You can always install an temporary aftermarket mechanical one to see (and hope) that it is only a problem with the gauge, and for a little peace of mind.

C3 4ME

If it's mechanical, you may need to bleed the line.

blue427

what do you mean "bleed the line"

wfo76

For 74, they switched from mechanical to electric so I would guess the sender could be going bad.

Mike Ward

jn01

Thanks to all. I'll attempt to deal with it again, this time armed with info from my fellow C3 brothers.