Q: I have a 1985 Camaro Z/28 with the 305 TPI in it. When I was just cruising around, I glanced at my oil pressure gauge. One minute it was normal, the next it registered zero! As I was driving home, I noticed the gauge would register 5 psi at around 3,500 rpm, so I knew it wasn’t the sending unit.
When I got home, I removed a valve cover and found out I was getting no oil to the valvetrain. I removed the oil pan to check the oil pump, and it looked fine. Needless to say, I’m stumped.
If I can’t solve the problem, I was wondering if I could swap in a 350 short block and use the 305’s TPI setup.
A: The oil pressure problem is a bit of a mystery, but we have a few things you may want to check for:
- A restriction in the oil pickup tube
- An open oil pump bypass spring
- A loose oil pump bolt between the pump and main cap
- A loose or missing oil gallery plug
- Low oil level (obvious, but did you check?)
If you do decide to swap in a 350 short block, you should use fuel injectors from a 350 TPI setup to prevent a lean condition. You can use an older short block as long as you keep the cam timing reasonable, around 208/214 degrees of duration at .050-inch lift and .450-inch valve lift.