What distributor is best.

Hello there I have a mud drag pickup with a 454 bored .030, 781 heads 10.25 compression with a 268 cam, It makes pretty good power, but it seems lately that I have a miss at idle and I can tell its not as smooth as before when I free rev it. New AED Carb 750hp. Motor was new at begining of year with about 8 races on it. Plugs, Taylor wires, and optima battery new when put motor in, The question is I using my brothers mallory HEi disributor, its about 5 years old I'm thinking thats the problem but I don't know what I should get to replace it. I would appreciate any suggestions from you guys what would be best for it. I don't get over 6000 RPM. I was thinking going with the MSD 6AL but I don't really think I need to spend that much money for onlly running 5800 RPM. Also running pure racing gas. Thanks

hop up gm HEI. but i would go for the msd with the 6al try a new set of plugs and wires?

I've used a couple of the MSD "plug and play" distributors, no complaints.

What ones do you mean by plug and play. The part numbers please. Should I just sell that mallory and start over with a regular HEI unit and upgrade it with some MSD stuff, new weights, springs, bushing, cap and rotor. I just don't think I need that really expensive stuff for higher RPMS since I'll onlly be max revving to 6000, for 150 foot track.