First time engine build won't fire

If you pour gas into the venturies;FIRST,move the car outside, away from any valuables.
Then;you better have a fire extinguisher nearby,and if you see flames, use it!!
I don't like that idea at all for a newbe.

Start with a properly filled carb, then follow post #8.
Once it's running post #12, has it covered.

I just gotta add, that it sorta sounds like the intake valves are not sealing. Normally I would suggest a compression test, but with the break-in lube being cast off the cam with the already excessive cranking, I'm not so sure at this time,that it's a good idea. .
So if you just can't get it going with the above helps, Then, do a compression test. It may be that your valves are not closing. But it's too early to go there, just yet.