not real familiar with the msd boxes in conjunction with the stock TB distributor and coil. Curently I have the dist.'s and coils. i have the 500 hp modules however not sure if they will work with my set up and there is many more pin connection from that of the older style 4 pin that I was originally looking for. If you msd boxes may complete the system i would be interested.
thanks,
john

msd 6520
 

6520