225 Porting

well my "447" head is at the machine shop for finishing and guide/exh valve seat install.... when I 1st dropped it off teh machine shop owner was like "Oh my GAWD".... I took it in thinking I'd screwed something up to begin with, being my 1st try at porting a head that hadn't already been deemed "scrap" for some other reason.... I actually took 2 heads in, the 2nd of which I hadn't done near as much grinding on, just in case I wrecked the 1st one.
Well he called me today, FINALLY had my block done, so I settled up with him on the block work, crank polish and hang the rods (NOS!) onto the new pistons, and he showed me, he has gotten into the original head that I started on and he said "I had the right idea, and what I did do looked real good".... I wasn't wanting much more porting for fear of hitting water, the machinist didn't do much more in the bowls, said I had them "pretty good" but was working on the ports a bit.... I wasn't gonna go there, since I hear so many say that the biggest improvement is in the bowls under the seat area, so that was where I had spent my time.
Machinist said I should pick up "around 20HP" just by porting that head, all else being equal. Sound about right?