I am by no means an expert on engines, but it seems to me that engineers put these engines in larger vehicles (like full size, extended cab, long bed pickups) and do not worry about it. I myself have chosen the magnum over the older 360, for reason of newer metal, less abuse, and newer technology (ie. roller lifters, etc.). Since the technology of the 60's and 70's helped pave the way for today's newer technologies, why not use it to your advantage. With the exception of the torque output of big block engines, small block engines can move a proportionately ratioed mass the same way. Also, power adder technology has moved from the racing circuits into main stream enthusiasts, which is lighter and tuneable (unfortunately more things to break eventually).