I have a 91 camaro z28 with the 305 i fust bought it had been sitting 2 years i replaced thwe furl pump and got it runnihg it ran fine no engine nojse at all but the oil pressure was fluctuating so I bought a new oil pressure sending unit and changed the oil. iam now getting no pressure on my gauge and the engine is rattling

 

What do you mean by "rattling"? If there is no oil pressure, the best thing to do is NOT run the engine, until you find the problem, and fix it. If it had been sitting, there is usually a reason for that, maybe the oil pump is going out? I dont know how far into the engine you want to go, but I would pull the distributor, and get an oil pump priming rod, and spin the oil pump over with a drill and see what the gauge reads (may need another person), or see if you can get an aftermarket mechanical oil pressure gauge, and see what that says. Either way, running your engine without the proper lubrication, will only result in further, more expensive problems.

Good luck!

 

no i turned it off in 15 seconds