>>Popping and backfiring leads to me to think it is an
>>ignition / timing problem - especially when it's out of the
>>carb. Pull a vacuum line of the intake and see how it
>>runs....vacuum leaks usually have a lopey idle and sometimes
>>won't allow the engine to run without giving it gas. You mentioned
>>ignition is new, have you checked the points and condensor
>>or did you upgrade to electronic ignition?
>
>I put in a new set of points and condenser, cap, rotor,etc.
>No new coil though. The engine idles fine but coughs when I
>get on the gas with a load on the motor, its fine to rev in
>neutral. There's really only one vacuum line running from
>the carb to the vacuum advance and puting my hand over the
>intake doesn't speed or slow the motor any, so I don't think
>it's a vacuum leak. I did notice the advance springs on my
>dizzy aren't tight, but I don't think this would make such
>an overnight difference. I have a electronic dizzy but no
>ignition box, what year truck would I need the box from to
>switch over and see if that takes care of the problem? Thank
>a bunch-Mike

With points/condenser ignition you have to be really careful with dwell angle and point gap. Too much of either and you can idle but once you try and get on it the points will bounce and you'll have the engine backfiring all over the place or even dying. Double and triple check your point gap and dwell angle. Point gap should be .018-.020. Can't remember what the dwell is on these engines. I used to gap points on a 144-170 with a match book cover. It was close enough to get it started and once I 'd find dad's feeler gauge I'd set the gap to .018.

Also if the gap is off, this will cause the coil to eventually go bad. The symptoms you describe are common to coils of that era. You're fine while idling but when you load it, it wants to die, due to coil not being able to recharge fast enough.

Check the coil for shorts and opens. Your Manual should tell you how.

Larry