HEI distributor on 400 big block in 1974 Dodge Dart Sport

I got the distributor yesterday and the cap was cracked and the red wire on the harness had a slice in it (from the extremely sharp edge of the distributor). I sent the seller an e-mail and shortly thereafter received a reply stating that a new harness and cap will be sent out to me first thing Monday morning. No questions asked and without even seeing any pictures. I thought that was pretty cool this day in age.

What coil would be a good upgrade? Is there one that will fit in the stock location on the cap?