Lynn-For the better cooling,thicker decks,better webbing,thicker walls that don't move around and thus reliable consistent leakdown testing,etc,and really considering all that for not that much more money,it is certainly money well spent.I promise you Lynn we have run afew of these and the OEM stuff just doesn't compare.I'd almost go out on a limb and say if you had the same internal components in a OEM block and a aftermarket block,the aftermarket one would out perform.