I need help with I am getting no oil pressure from my motor I just rebuilt first time rebuild it is a Chevy 350 out of a C20 pickup can anyone help

check for vacuum leak for the idle or idle mixture screws settings
no power in 3rd gear can be low fuel level, filter problems , ignition timing ( static is 12 degrees BTDC idle )
more than likely a vacuum hose missing after assembly

Hi
You need to remove and clean with a carb cleaning product the carburettor and air blow it
Catalin

the only things that are rotating to give a grinding sound are
the crankshaft, cam shaft and starter motor
for the crankshaft it could be slipper bearings too tight and are now spinning in the caps, missing thrust bearing halves on the crank shaft
on the cam shaft -bolts behind the cam gear touching on the back of the gear
oil thrower disc in wrong and the edge is running on the cover of the timing chain housing
starter motor not in correctly and jamming the pinion in the ring gear while the motor is running( some 350 motors have a shim adjustment for the starter housing to block
It is difficult to say exactly but if you followed the workshop manual to the letter you will know what you missed

This is an oil PRESSURE issue, not oil level.
It is likely that when you stop, and the engine returns to idle, the oil pump is not creating enough pressure to push oil up to the top of the engine and lubricate the valve assembly.
I hate being the bearer of bad news, but the plastic impellers in most modern oil pumps do fail over time, especially if they've been disturbed by the work associated with an engine rebuild. Or, it could be that it is not sitting right on the pickup and feed tubes, and they are being blocked and causing pickup problems at low RPMs. The solution will involved dropping the pan to figure out what's going on with the pump.

Nothing. Also it will be much cheaper to find a used matching transmission with low (less than 80k miles) than having a shop rebuild the old one. In most cases the used transmission will far outlast the rebuilt one. Check on the web by Googling "used transmissions".

Change the oil pressure gauge and use heavier oil such as 10w40 or 10w50 if you have more than 100k you may want to use 20 w 50

Hi shwangod, you said it was a "heavy knock" and it began climbing a hill, could you give me a little more info, mileage, overall condition,2 or 4x4 am assuming this is a small block 350 cid, obviously there are different "knocks" for different problems, lifters do not knock they will click or rattle and are easy to adjust, a timing knock is the resultant effect of incorrect timing usually on the low side and is also easy to determine.A wrist pin knock associated with the piston boss pin can sound like a main bearing knock and is worse when the engine is cold and will subside as the engine warms up, the main bearing knock is the heavy knocking that doesnt quit and can lower oil pressure (operating) you can plastguage the mains to determine the amount of wear and if you are lucky you can roll in a set of bearings, when you drain the oil look for metallics, specifically brass, personally I am not a fan of upper or lower engine rebuilds but prefer to "Rebuild" the entire engine. I hope this helps you,good and let me know how you make out.

You should be fine. the same oil port feeds both sides of the lifter galley, it just splits and goes to both sides. fire it without the valvecovers on it or at least that side. you will have oil shortly. many different reasons for this. try to turn the engine 180 degrees if it really bothers you. its good to be thorough like you are but you'll be fine.
Good luck.
Please rate this response , and let me know if ya need more help!

Have you tried replacing the water pump? Sounds like the water pump is not circulating to water.
Hope this helps!
CastleTowery

Don't bother rebuilding. If it lost oil . it's a goner. Check around town and see if anyone sells used Toyota motors shipped from Japan. They have to get rid of all vehicles with 50.000 miles by law. Wholesalers in the USA buy them cheap! I got one for my 87 MR2 for $1200 installed. Runs like a champ! SR5 engine are very popular , so you should have no problem finding one in a large town like Denver. Remember, get a warranty, even if it's for 90 days. Gives you that warm and fuzzy feeling! :)