I've been trying to get my carb running right on my 414 stroker for a while now. I haven't been able to get it to idle below about 2000 RPM without dying. I took it apart and blew it out, and found a couple chunks of plastic in it, so thought I found the problem. When I started it, it started right up, but still wouldn't idle below 2000 RPM, although I never got it warmed up enough to know for sure. I let it die after a couple minutes, and when I tried to start it again, the engine turned backwards for about 3 seconds...several revolutions.
The timing is locked out at 30* with a 20* start retard on an MSD E-Curve.
Carb is a Proform 750.
Compression is 10:1 with Iron Ram heads

Could I have skipped the timing chain when this happened? What all do I need to check??