Tough call I don't think there's no real way to be 100% sure I would'nt think a 428 would be that much heavier, if it is you're already liting it up with the alum. intake but just to be sure you may want to go with the coils for the a/c car.I don't know if you've ever replaced coils before but if you hav'nt make sure when you're putting them in that where the coil starts on top that it fits into the groove on the upper arm so that when your done the car will sit right (made that mistake before!!)I always drop the lower ball joint to get mine in.