Edit: The topic was supposed to be power loss, but it's 1:20am so forgive me

Car:
1987 iroc 83k miles,
Stock 305 auto, ONLY mod is a dual exhaust (new headers and everything).

So I was at the track, and my car ran fine the first pass but then got consistantly slower (by about a half a second per run). It didn't seem to be running rough or badly, it was just getting slower. I gave up on running it, and later that night I drove it home.

On the drive home it seemed to regain some of its power, but then I noticed a slight knocking noise. It was intermittent, I'd say about once every couple of seconds or so. As I was driving the noise steadly got more constant and I lost power. By the time I got home it was knocking along with the rpm of the engine, and I had absolutly no power, it could barely make it up a hill.

Another note, my oil sending unit/gauge started acting strangely at the same time, it was moving ALOT, sometimes going to 0, sometimes pegging the gauge. I checked and the car has oil, not sure if maybe the oil pump is going, would that cause such drastic changes in pressure?

Any thoughts on what the noise might be?

 

id say get a 350 or another 305 and have it rebuilt .sounds like you've got a spun bearing.

 

Thats what I thought it might be, but when I rev the engine to around 2,000rpm, the sound seems to go away and come back intermittently, then when I drop it back to idle it goes quiet for abotu 5-10 seconds before coming back.... can a spun bearing do that?

 

Spun bearings can do about anything they want. It may not be a bearing but what ever it is it sounds like the motor should be pulled apart before it becomes an anchor. A real outside chance, but it happened on my 305. When it started up it sounded like a bad bearing, but what had happened was the flexplate bolts had started to loosen up.