OK what cams are you selecting, also IMHO I'd take the $1000 for the hd heads and spend it sending the heads to SBC
www.motorcyclemachine.com or
www.tmanperformance.com or
www.undergroundheads.com,
You'll end up with a custom head spending the same or less for better work than a cast head, and you should pick the cam and let the heads get worked to the cam. This is the best method for making good reliable power.
If you go SE heads they are not bad and they do help quite a bit but the shops listed above are good.
SBC got backed up big time when HRB did an article on the great work and inexpensive costs. $400 or so, they like the tw-37b cams from andrews.