I have a couple of questions about the MSD ignition systems. I have a 76 with the original 350 hooked up to a TH350 and the stock HEI system. Will an MSD ignition make a difference? If so which is the better one for a daily driver? OffRoad or 6A? Other? Would I need a rev limiter to keep the engine from over reving? What is the max rpm for this engine? I am looking to get more power, better combustion because of polution laws, better gas milage and a smoother running engine. If any of you have any experience with these let me know. Thanks.