Well, this will be the 3rd time I've tried to post on this thread. This time I'll copy it before submitting, so that if it don't go thru, I won't have to type (the 2-finger hunt & peck system) it again. This is my 1st day here, so ya'll bear with me, please. I'll get the hang of it.
OK, the OP stated that he didn't have $2400 to spend on alum heads. So, that begs the question, what is your TOTAL budget ?
That will determine what parts and machine work you can afford. For example: if $3000 is your total budget, then you will probably be limited to the #17 heads you have, cast pistons, cast rods, and a Summit cam kit. The amount you can spend on upgrading the heads will depend on what the rest of the build costs. It will be best to get new stainless steel valves, hardened seat inserts and a GOOD 3-angle valve job, with new guides and seals, as well as having screw-in studs installed. But, if there is not $ for all that, you'll have to make do with less.
Just to give you an idea of what stuff costs, here is a 350 + hp, 400 longblock crate engine. It will run just over $4000 shipped. For a couple of hundred more you can probably get forged rods too.
This time I'll copy it before submitting, so that if it don't go thru, I won't have to type (the 2-finger hunt & peck system) it again. This is my 1st day here, so ya'll bear with me, please. I'll get the hang of it. 
