Fresh rebuild issues. Timing off by a tooth?

[vannatta20]

got a customers 69 in today and went to fire it up today.
Engine is a rebulit ls1 by local no name shop that does not build ls engines much...
228 228 duration cam with 588 lift and 112 lsa. stock heads ls1 intake and has long tube headers. Open headers for now. No 02s.
At first no fire at all. Turned out all 8 injectos were stuck. Fixed that and tried starting. It finally fired but could not idle below 1400 rpms. Ive tuned quite a bit of cars and knew what the base settings should be. Next I played with idle air flow and that did nothing. I then locked the timing and started raising it. It was at 22-24 degrees. I upped it to 36 degrees and it would finally idle. Sounded crappy but all cylinders are firing. Why will it only idle at 36 degrees to 40 degree...Once it could idle i had to change the idle airflow back to a decent range. This car doesnt want to even fire up with timing in the 20's.