If the cam is advanced then the intake valve will close sooner, which will raise cranking compression by trapping more air in the cylinder. Normally at low speeds some of the mixture gets pushed out of the cylinder as the piston passes BDC and begins the compression stroke. At this time the intake valve is still closing, so some of the charge escapes. If you are off a tooth or two on the timing the intake valve will close much closer to BDC and very little cylinder pressure will bleed off, thus raising cranking compression. This will make the engine run like s**t until it is spinning a decent amount of RPM, though even at high RPM's it may still not run quite right depending on how far out of whack the cam timing is.

 

if I were you I would take the timing chain off and recheck the tchain alignment. detonation will also kill eng. bearings pretty quick and worse can cause all kinds of destruction to your new rotating assembly.
also, if the chain is right, maybe youd want to degree the cam. that way, you can be positive its the right cam, and its cut correctly.
also, my cam idles at 850rpm and has no surging/bucking or anything.