I'm spent... need some ignition advise.

Put a new engine in my truck ('84 ram) and now i'm down to tuning it. I can't seem to get a timing light to work on it. I tried 3 different timing lights but the flashes are very erratic on cyl 1. cyl 3 seems to be a little better (just tried for comparison) swapped cap, rotor and new plug wire. Doesn't seem to help. The truck will idle and rev but dies under load, all cylinders fire but i'm sure the timing is off (unless i got really lucky). Just rebuilt the eddy carb. the timing light seems to be better at higher rpm. The coil is new but cheap parts store brand. I'm going to start with a new msd coil. I'm also looking to upgrade the ignition as it's a pretty built 360 with stock/stock replacement ignition. Any recommendations without breaking the bank? I'm just starting to get frustrated with it and looking for any guidance. Thanks guys.