I guess the depend- depends if the cyl head needs to be replaced or can be cleaned and refurbished and reused. The 12 valve head on my old C8.3 had to be replaced with a crack near one of the valve seats making the engine lose water. The ISC's have 24 valve head that if can be re-used makes the inframe cheaper, a couple grand or so more expensive if replacement is required. Only a removal and inspection of the head can determine this. Denny