You should use either an MSD Blaster II or Accel Super-Stock round coil with ALL HEIs, small or big body. The stock, and even performance in-cap coils are the worst thing an HEI has.
MSD makes a coil cover that allows the coil to be moved out of the cap. This lowers the undercap temps 40 to 50 dergrees, gives an oil filled coil, instead of the seriously inferior epoxy filled coils.
All the HEI people who insist on keeping the coil in the cap don't tell you that the amount of voltage output GOES DOWN with the heat the coil produces within itself when it gets hot. Even the highly touted 50,000 volt coils, that never did or will make that kind of voltage-even cold, will drop even more performance voltage off when they get hot.
This is the main reason I do not work on, and will never build a coil-in-cap small HEI. All my systems require a remote from the cap coil mounting, it is just the best, and only way to do it.
Point design stock coils have the wrong windings turns ratios to work with an HEI, or to work without a ballast resistor.