engine busting up

I agree. Start by going to a fuel pump that will supply the carb 6-7 psi or one at 10 psi and regulate it down. Also the 5/16 line ain't big enough for that 750 you need 3/8 minimum. The bucking and kicking could be fuel vapor-lock and the higher pressure and larger fuel line will help but check your fuel line routeing that it isn't close to the headers or firewall. Once you've fixed that problem take a look at the advance curve of the distributor, try initital at 12-14 deg and 35 deg full advance at 2400 rpm. Don't forget to check all the ignition wiring and plugs.