I'm still gonna replace my 305 with a 350 but about a month ago while I was driving. My engine started making a loud knocking,I pulled over turned the car off a few minutes later I Started it&a puff of smoke came out of the heads.well before all of this my oil gauge wasn't reading but when I would check the dipstick I had plenty of oil someone told me it may just be my oil pump went out...what should I check idk id just like to know thanx

Remove the oil filter and cut it open. If you find bearing material in there
you will need to disassemble the engine to inspect.

&what if I don't find bearing material?

the first thing you should probably do is hook up a mechanical oil pressure gauge & make sure you have oil pressure. If you don't & the engine is making a knocking noise the damage is already done.

Also when I took the valve covers off I smelled them&they had a burnt smell

You probably haven't thrown a rod...

But you've probably ruined at least a few of the bearings. That would burn the oil and cause the knocking.

Throwing a rod is the next step.

If you don't find anything in the filter element it means the bearing are likely
in good shape. Check the valve train. When a engine makes loud noises it
normally leaves clues as to what's causing the noise.

If it's louder than a valve tick it is more than likely a rod knock or slack between the connecting rod/ bearing and crankshaft. If you "threw a rod" I can tell you that engine would not be turning over. You'll know if the rod comes loose. I'd pull the oil pan and see what is loose or going on from there.

I'm about to take the motor out so Ill see soon,but it was still starting but super loud

Well, at least it would have made a loud 'bang!' and there'd be oil dripping on the road...

But it's not impossible for an engine to keep running. A friend of mine had two rods break in a Range Rover (alloy V8 model) and just kept driving. He said it ran really rough and lost power, but he made it home!

start it up and hold it to the floor, you will know when it does throw it.

Must be the way we was raised Jim, I was thinking the exact same thing.

I agree with what Jim said. It's not like your losing anything major, its just a lil 305. Start it and hold that pedal to the floor.

I agree with Jim...blow er up!!!

We did that with a demolition car that we used. A 64 Lincoln continental with the 460 in it. No water, no cooling, but the engine was still running and started after the demolition. Since the scrap yard was going to pick it up the next day, we decided to have some fun. We started it up, and held the pedal to the metal. That engine was screaming for mercy, but would not blow. I think we never laughed so hard in our lives as to the punishment this engine was taking. After several minutes of this punishment, it looked like various colors of exhaust were coming out and the exhaust seemed to get louder, and then "Kaaboom!" The connecting rod came straight out the oil pan. That was more fun and more memorable than the demolition derby itself. I'm with Jim and all the others. Make a memory, BLOW THAT SUCKER UP!