Low RPM/idle with Lh2.2 and fully built motor??

[gottarollwithit]

We just swapped in a fully built/upgraded motor and the idle is rough and shaky. The idle AFR is about 15.1. When driving under 2k RPM in 1st, the car bucks b/c the engine speed is unable to hold or smoothly go up/down. So, if i drive slowly, i can feel the car jerking b/c the engine speed is very unstable at low RPM. When at higher RPM, it's fine though. If i shift from N into D or N into R, sometimes the engine dies as i click it in gear.

Any ideas why this would be occurring?

Granted, the RSI Stage 1 cam and using Dale's underdrive pulley probably aren't helping the idle, but that doesn't really explain the jerking at low RPM.

Outside of an MSD Blaster coil, the ignition system is stock lh2.2. I just cleaned the IAC and it didn't help. Before the swap, everything was working perfectly fine...

Any ideas???