it's not cheaper to buy new alum heads than to replace the guides, valve job and even new valves on iron heads. I've been thru this. as far as $650 for new sidewinders, that's great! but, what average guy gets any offer even close to that. give a $1000 for stealths and then blow another $500 to fix them. alum heads aren't a money saver on a project like this.

if it were me i'd put the extra money that would be spent on alum heads (the sidewinder deal excluded) in pistons.