Head flow and power differences question / discussion

The Indy heads for sure need ported as they kinda suck bad stock. The 245 Indy head can be an animal if they don’t leak and I’m not really fond of their exhaust port. Trouble is that if you get them ported there’s not enough material to fix it the way I like.
What I have are the 360-1 top end port and polished from Indy.
They claim 339 @ .700 lift

http://www.indyheads.com/images/t_pge/360_tech.pdf