Rough Idle and Hard to Set Timing

[madaba]

Ever since i swapped in a used 6-bolt motor to replace my blown one, i've had problems with vacuum readings and setting the timing to 5 degrees.
At idle the vacuum reading varies from about 14-18 depending on the actual rpm and decel is about 22. It also has a misfire at idle as well. When i try to set the timing, setting it at 5 degress results in the cas being back all the way and moving it foward advances the hell out of the motor, and it also runs smoohter advanced at about 15 degrees.
I just replaced the timing belt this weekend and nothing changed, all the marks seem to line up but i noticed that if i put the crank mark dead in the middle the cams are off a hair but if i move the crank a hair then the cams become dead on with the top of the head?
I've also replace the intake manifold, multiple tb's, the cas, coil pack and transistor, wires, plugs, extra grounds, pressure tested the intake manifold (going to pressure test everything tonite), replaced injector seals, egr blockoff, set idle, replaced biss o-ring. Used the carb cleaner spray method of finding a leak with no-luck. Ive also removed all the emission vacuum tubing according to taboo's website.
On my logger, nothing seems to be out of range except for idle timing is usually in the high teens, average about 15-20 with dips from the misfire.

Thanks

 

[TwinOptiX]

Have you had any luck on your problem? I have the same problem.

Do you show any knock with the ignition timing at 15 degrees?