I have an 83 chevy C-10 with a 305 4 barrel.. Ok i had the engine build alittle im pulling 300hp out of it... my question is the oil pressure used to be all the way up like at 60 and now the more i drive it the less pressure it shows now its below 30!! so whats up?? im about to lose my mind! its really making me mad! im already gonna have to take it to the shop b/c i cant get the detent cable working right! ( or kick down).. I do have a small oil leak its coming from the oil pan im gonna fix it tomorrow.... but what could be causeing this pressure to drop???

 

Is it a real pressure gauge or an electric one? If its the dash board gauge, id check it with a real pressure gauge before digging into it. Those electric gauges are noted for being inaccurate.
How old are the main bearings?

 

Generally when pressure goes down as you drive this is a bad sign....

More often than not it is your oil pump. The bearings in the pump are probably getting hot and swelling, which is causing drag and making the pump turn slower which will in turn decrease oil pressure. The more you drive the more things inside the engine get hot and swell in size. Generally this will increase oil pressure to the operating level.

There are other factors to rule out, but if there are no leaks, and the gauge and sending unit are good, and you are using the correct viscosity, the pump is the most logical place to look.

 

May want to just check the screen on the oil pump. Had an Ford that did that. Person that owned it before was using less than choice oil.

 

I rebuild the engine with all bearings upgraded cam and the works new oil pump... everything proformer intake and stuff like that.. I figured it out the sending unit was shot! LOL so im sticking me a guage in it tomorrow... Now all i have left is the detent transmission cable and i said forget it! so its sitting at a shop right now getting fixed... thanks for the replys though

 

Now that you mention that, we had a car that did that. And of course, that was the last thing we checked. [img]i/expressions/face-icon-small-blush.gif[/img]

 

Here is the best piece of advice I can give to any Chevy owner after having a 2000 3500 Crew cab 4x4....Take the Chevy over to a Ford dealership, take any money they will give you for it and get yourself a Ford Truck!!![img]i/expressions/face-icon-small-happy.gif[/img]

LOL, just kidding. As far as I'm concerned I'd drive any full size truck so long as it is a diesel.

TPR