I have a 1998 old Bravada same as a Blazer ... the issue I am Having is I just finished building the top end of the motor due to a cracked head. when starting the vehicle the engine makes a loud bang but when it starts it runs well... I checked timing again and just finisher checking the starter. one note when I crank the starter without the coil connected it turns over fine, it seems when the engine fires it causes the hardship ( loud noise and starting issue... any Ideas?

Now after another test drive it runs great... still having the issue with a hard start and have narrowed it down to possible the choke system if that's possible... like it is not getting enough air and then causing a drag ( hard compression at ignition ) like I said , when it starts it purrrrs

 

The distributor is not timed correctly with the camshaft. When it's running, is the check engine light on? If so, retrieve the DTC's. Most likely you'll find P1345. If that's the case, post all of the DTC's in the order they are retrieved and we can help you time it correctly. Very easy, if you know the trick. If it starts and runs, it's close, but it's easy to make a real headache out of it if you don't do it right