Installed a new GM crate engine in my sons "79 K10 this week. Got the engine running, did the breakin proceedure and took it for a ride. Engine is an absolute DOG!!!! The first indication of trouble was the engine needs a ton of initial advance to stay running as well as a the idle speed screw turned in almost till the spring bottoms out. If I try to set the timing to stock spec 8 deg before it barely stays running. Putting it in drive kills it. I verified TDC at the piston, valves closed, rotor pointing at #1 on cap etc. The dist is a remanned unit from napa and worked fine on the old engine, tried the original carb on it then swapped a Jegs Hotrodded Qjet on it with no improvement. It drives OK other than the rediculously high idle it needs to stay running in drive, but when you punch it, it doesn't accelerate, just continues on and slowly starts to load up. The original carb does the same. The manifold vac at "idle", 1500 rpm or so, is 22 and the ported vac is 15. The vac can on the dist does advance when I pull a vacuum with my MightyVac, the advance weights are free. I'm at a loss as to what the problem is. I plan on pulling the timing cover tomorrow to verify the cam is installed correctly. Does anybody out there know for sure if a SBC can even run if the cam is off a tooth either way? I'd like to have this fixed by sunday so he can drive back to school in Conn.