Could be the advance weights are taking it too far -wear on the backs of the actual weights and on the stops but in all my years of keeping "end of life" vehicles going for another couple of months this wear has always been negligible
what is more likley is that there is either an induction leak, fuel starvation or you are doing something wrong with the timing.
leaks are found by spraying wd40 brake(break)cleaner or the like at the carb base and manifold joints any change in engine note or speed indicates a leak
check that the fuel lines are all ok and that you have new modern rubber, pay attention to the bit on the top of the tank as well as the actual sender steel pipe.
then if your leads and plugs are good you can go about tackling the points, cheap "Intermotor" brand are rubbish best get a set of Ducellier-Valeo ones from a decent source the mis shapen intermotors always seem to have the points box at a j"aunty angle" when the timing is set correctly.
set them as per haynes and if you time it statically retard it by the eqivalent of about 1 tooth on the flywheel.
find that in the UK using cheapest unleaded:- tappets at 0,25 slightly tighter on the inlet, 0.4 points gap(or 53* on the dwell meter 4cyl4str) and sllightly retarded - strobe it to a max advance of 32* which is just off the "7th tooth" method of dynamic timing-and a nice set of NGKb7s works lovely
nothing too contentious there i hope
Oh and lid off the carb and blow out all the jets and drillings.
