Fresh rebuilt 460- bored 20 over only thing reused was crank, it was polished and we used the distributer. Motor fires, lots of fuel, crank timing correct, good spark it will not run ...HELP

An engine will have an injector for each cylinder it has. So a four cylinder has four, a six cylinder has six and so on.
If it has been stood unused for that long the first issue could be the fuel. Fuel over time can go bad and leave a varnish like coating on the fuel system parts. Drain any fuel in the system and tank and SAFELY dispose of it then refill with fresh fuel.
What EXACTLY does it do when you crank it? Just winding and no attempt to fire is often a spark issue. Cranking and trying to start is probably a fuel supply issue.
A simple starting point is a basic service on the vehicle. Fresh spark plugs and a new air and fuel filter with the fresh fuel should make a difference. Only remove ONE plug lead at a time to avoid mixing them up and keeping the firing order correct.
Before removing the first spark plug crank the engine for 2 to 3 seconds. Then with the ignition key out remove the first spark plug and smell it. if the injector is working you should smell fuel. Refit spark plugs gently by hand and don't over tighten them to avoid stripping the threads out.
When cranking do it as lots of 2 to 3 second bursts as this doesn't flatten the battery as fast. It might take a few attempts cranking to pull the fresh fuel through to the injectors.
Use the comment button below if you need any more help.

If you made no changes to the fuel injection computer to tell it that the displacement has changed from boring the cylinders 30 over, it will not know to add more fuel from the injectors. Engine displacement is programmed in at the factory.

sounds like you're wasting lots of cash. Check engine codes? take it to a shop and pay by returning all the unneeded parts? call a cab?
Please tell me you can use a multimeter and read a manual.

check for spark first,either with a spark test light or the old fashion method- screwdriver held close to metal,if no spark- distributer could be the culprit

Dump a tiny bit of gas, just a splash, into the front barrels of the Holley and crank the engine. It will start and die. do it again until the fuel is up and it keeps running. If it don't keep running, your either out of gas in the tank or you have blockage in the fuel line from tank. That's all it could possibly be. Period. Fuel pump is making pressure and pulling, it WILL work.

I would check the compression first. Without compression it won't fire. I should be at around 160psi per cylinder. If any are below or varies 10psi per cylinder, then the engine needs to be rebuilt.

Pull a couple of the sp. plugs out and see if there is fuel on them. If not pull the o2 sensor out of the exhaust and see if it starts. It will run rough but should start and run. If it does start you have a plugged catalytic converter or muffler and it is putting back pressure on the engine and not allowing the fuel into the cylinders.

Did you drain the old fuel out of the tanks? Old fuel will not fire most times it goes bad and mosture accumulates. Next question for you are you getting and spark?

look at the ignision system id say the distributer or coil pack

because you said it sounds like timing problems i may have an idea. i dont remeber if these have a distributer? but its common for the distributer on the newer GM trucks and i dont know why but its like the spark jumps around inside causing incorrect firing order when trying to start and just gets worse and worse. remove and inspect for build on on rotor and tabs on distributer.

and get back to me with problem
plz rate
Michael
ASE certified