Yanking hard at idle???

262/268/112+4
Nice city cam. Great teener cam.
If the engine is mechanically sound,I can make that cam idle at 550(neutral),maybe even 550 in gear.
You should be able to set it to 700N, and 600in Drive,easy enough.
Yes 30* at idle is crazy. Back it down to 10 and get after the T-port sync.

I guess you don't know this, but the more timing that you throw at the engine, the higher the idle will go, .... with no other changes, until the engine doesn't like it anymore, which might be as high a 40/50 degrees.. Try it. Back the timing down to 10*, and just pull on the can until the engine stops increasing in idle speed. Then read the timing; you will need a dial-back light or a timing tape.
That said, you can't drive it with the timing maxed out at idle.
Every rpm and every load setting has a very small window of preferred timing. If you are too low;performance or economy will suffer. If you are too high, the engine can or will go into reduced power output or detonation; which must be avoided at all costs cuz the the engine usually breaks something sooner or later.
Mattax printed a nice timing curve for you, (post 24) with accompanying good advice.
But get the T-port sync set before you start messing with the distributor.
Learn about the Sync here; AJ's guide to Transfer Port Synchronization
Also, check out this thread;
318 stalls in Drive post 27