1984 Corvette overheats and oil pressure drops

[Ewing]

I have a 1984 Corvette that I purchased last November. I recently had to drop a new motor into it. About 500 miles ago, I put a rebuilt longblock 350 in it. It also had a 3 stage fan controller added to help with cooling issues at the time it was installed. Since then, it get's up to 255deg and when stopped, the oil pressure drops into the red. This seems to happen more going uphill. On level roads the temp runs around 225 to 230. I live in Seattle and temps are normally in the 70s this time of year, but have reached the 90s over the past few days. Mechanic that installed the new notor couldn't find anything wrong with the cooling system. Any ideas? I'm at a loss.

[c4c5specialist]

HI there,
A mechanical oil pressure test should be done, along with checking for debris in the radiator.

225/230 while at highway speeds is too high.
You should be at about 190 at highway speeds, unless your heavily modified.
Allthebest, c4c5

[Ewing]

I'll check those things. There are no modifications except for the new long block instead of the old short block. The old motor ran hot as well, but I didn't have the severe oil pressure drop when stopped. Mechanic told me it's dropping so low because of the high temp, but couldn't help me with reason for high temp. I had them check between radiator and AC condensor, but nothing there. Radiator was suppose to have been flushed when new motor was installed. Thanks again for your help.

[c4c5specialist]

Hi there,
NOT INTERNALLY< externally debris can build up in the fins, creating a loss of airflow through the radiator.
If they did NOT do an oil pressure check, THERE IS A PROBLEM AND SHOULD NOT BE DRIVEN>
Allthebest, c4c5