I have a 355 with a stock HEI conversion. When I try to accelerate the motor pops and (usually) dies. Ideas?

Question

Too much or too little timing or maybe a carb problem? I have been working on Ford EFI for years so carbed chevy motors are a tad Greek so please speak slowly and use small words. =)

Answer 1

Brian, you may have made a mistake that is very common when installing the stock HEI distributor.

You probably used the wire that went to the positive side of the coil on the old breaker point system. However, this is not a 12 volt wire. It is a ballast wire that reduces available voltage to the ignition system. If you have any doubts, test the voltage to it when the car is running. You will find it is probably about 9 volts. HEI doesn't like anything less than 12 volts. If this is the case, you are going to have to find a 12 volt source that is hot in both start and run.

When finding a source wire, don't just assume that because it is hot in run, that it is also hot in start. You will be surprised that most 12volt run sources go to 0 during start. If this happens, you will have a vehicle that wont start, or it will try to start when the key is released from start.

If you are absolutely certain that you have a good 12 volt source and it still does this, I would look at installing a GM 1 wire alternator. It will give your HEI system about 13.5 volts to work with.

Answer 2

need to check base timing and if that dont make it run check timing chain and valve adjustment got an intake valve opening to soon

Answer 3

ensure the cam is installed straight up, set the timing straight up, that should give you a pretty good baseline.  if the problem continues it is most likely a carb problem, such as inadequate fuel due to jets that are too small, the problem could also be floats sticking, or a bad accelerator pump depending on the carb.

Answer 4

sounds like a fuel problem so id start with a filter change andor add fuel treatment.. and yes it could be timing also so have you check that  

Answer 5

check the timing, make sure the spark plug wire are in the right order.  double check the setting of dist.  

Answer 6

is the carborator a holley you could have blown the diaphram in it