I've got a new/rebuilt 350 in my 1989 suburban. I Just finished buttoning her up this weekend. Put in oil and coolant, went to start her and she won't catch. Just spins the motor. Here are the facts. 1) Starter sounds funny...like it is spinning too easy...I don't get the grrr--rrr-rrr of normal starter, I just get a high-pitched spinning sound. It is turning the engine over....but it just sounds wierd to me. I did drop the starter on the concrete while installing it...but if it is turning the engine over that is all that should matter right? Could a slow starter prevent her from catching? I did notice that the starter drive gear doesn't retract back into the starter? It stays engaged with the flywheel...but I kind of remember that the force of the engine starting is what sends it back into the starter housing? So since my engine hasn't fired, it is just staying engaged with the flywheel...is that correct? 2) After I try starting her...if I let it sit for a few minutes...then bump the key she backfires out the exhaust?? It won't back fire while I"m trying to start her...only after I let it sit and try to start it again. Can't figure this one out...makes me super suspicous of the timing. The only way it could back fire is if it is sparking with an exhaust valve open right? 3) I do have spark...checked against the body of the car while cranking. 4) I do have fuel...it is spraying into the intake from the throttle body. 5) I'm 99% sure my primilinary timing is set correctly. I've got the rotor very close to the #1 contact in the cap when #1 is at TDC. I've messed around moving it a few degrees left and right from there without any change. I had my girlfriend crank it over while I watched the timing light, and I couldn't see the timing mark when the timing light flashed, but I couldn't see very well period. But I know for a fact, that my distributor is NOT off 180... Any ideas?? What is the most typical part of ignition system to fail? All these parts were on my old engine and it was running when I took it apart. Thanks all ideas and help!!