Head upgrade
Kind of depends on who ports them. I would put Advanced Induction and TEA's port work at the forefront of CNC porting for the 243/799 heads. With them doing the port work and milling the heads to achieve maximum compression, anywhere from 40 to 50 more would be possible.
I gained 42hp/41tq from 90/90 intake cam only to TSP stage 2.5 5.3 heads and Harland Sharp roller rockers and LS6 flow even better so I'd expect at least 40 from TSP, TEA or Advanced Inductions, can't go wrong with any of those porters
