Buy as much horsepower as you an afford. Either BB or SB works great. These SP can take as much HP as you can throw at them.
Best driving ones I have been in run from 430HP to 600HP
Get a roller engine with MSD and you will only have to change
oil and do a small amount of maintenence. My last cobra had solids, dual point, ect and I got tired of working on it. Build it to drive and enjoy.
Hope this helps
Mark