is alu. heads...
I agree with what brack. said
For you if your putting money into something it is my mind that you get the best you can afford (within reason)
Thinking is that if at some point this goes from street car to strip car there ya go. Your one step ahead of the game and won't kick yourself in the pants thinking "geezs I jsut put heads on 2 years ago... I saved 300 then but now it will end up costing me twice that!... "
If you can use race gas then the 64 cc heads wouldd be good for you. Mix it with a little pre. gas. The 11:1 comp will make for a really nice set up.
The rpm intake or rpm airgap for sure
ST. plugs are really all you need. Angle plugs where suppose to be for better burn in the combustion chamber but the results are moot.
Now if you just get a cam to tie those together you will have a very nice combo.