I done both when I did my current mill.Just remember all of the costs when stepping into a basic EZ head It wont end with "just heads" whoever sets your heads up(do not just buy them from Indy and bolt them on)will recommend a valvetrain and cam setup when you decide which heads you want.I would stay with the top end you have and get that heavy,old rod and piston set,possibly cracked crank,and get a good base for your new heads for next season
Gus

Lots of great advise... any others opinions out there? Thanks guys.

Your current iron heads have oversize valves? Anything else done to them? They sound like decent heads. Id do the stroker shortblock- get the hard part out of the way and have the improved low end and mid range punch. Better heads and cam will be simple future bolt ons.