with the alum heads you can run one point more cr with them .i think i talk to you about this before. you may cut the dome down some on the pistons if need or just buy a set of pistons for cr you want with the heads you have hard to say. if you look in side of the heads there will be numbers that will tell you what they may have been? why do i say this older engine hard to say if they have had been cut ALOT on heads this would be up to you them 800.alum heads new on e-bay i do not know any thing about them so if you want to throw 2300+ on a good set of alum heads then go for it but the heads you have may be good it will not take any thing to move your car and the alum heads will help on the front end weight but that is up to you