What Cam and lifter set for stock 1965 273?

There is no such thing as "Hi-Po Commando " 273 heads...all 273 heads are the same...2 or 4 barrel. The higher compression of the Commando/Charger 273 comes from the pistons (domed). . Now if you want to replace the heads, I'd go with a pair of redone "'302" castings. With a 4 bbl carb and intake, I'd go Isky E-4 cam(closest to orig Commando solid cam available now). PM "toolmanmike" for his opinions...he has one.