OK at the risk of sounding stupid I'll bite, what's the extra expense of Al head going to do for me. We're only talking one, not two as with a V8 and the cast heads are not monsters so weight difference can't mean that much can it? I'm already throwing away the money I put into the 200 cast head with the Clifford performance kit only having a few hundred miles on before I realized I'm pumping a dry well on going faster with that. Now before you guys start telling me you gotta pay to play. I have several cars I'm working on at any given time and, with the excpetion of the 66 fsk 6 waiting for the snow to melt, they all run and get their share of investment to stay that way. If were talking night and day power gain over the cast head maybe you can get my attention but, would the cast head with the extra $500 not spent for Al put into a good ignition system be a better path to go faster?