correct they are heavier, getem tho. i am running a set with weisco pistons, and acl rod bearings. my motor the way it is built will hold about 16 psi before the cylinder walls go. thats only out of a big turbo tho, that moves ALOT of cubic feet of air per min. sacrifice a lillte wieght for awsome power and tunning potential. oherwise youl be replacing them anyway.