about a year ago i rebuilt my 305. my old crank was no good and i had to buy a new one. the machine shop i was getting my block done at just happened to have one in stock. when i got it, it was labeled for a 350. no big, same crank right? so heres the issue

ever since then, it has idled rough and vibrated tons. when i try to time it, it has to be 60 degrees out to even run. my thought is at any point was the key on the 350 crank 60 degrees off of from the 305? has anybody heard of this?

 

A 350 crank is balanced differently from a 305 crank. Remember 350 pistons are heavier right? So if they didn't balance it for you, there's why.

But it sounds like you're one tooth off, or the damper ring has slipped anyway. If you've got the wrong balancer/timing tab combo that will do that as well. Very common thing (where's sofakingdom lately??).
Throw your timing light back in the toolbox for now, time it by ear. Bump up timing until it pings under heavy throttle high gear high load type of deal, then back it off. See how it runs then.