The combo all comes down to what exactly you want from the setup and what you expect to get and where you expect to make it. You can go pretty large with the atmosphere charger as long as it stays efficient for the range you are using the truck in. Putting a 488 over a 72mm and expecting to tow with it at 1800rpms and you are going to be pretty sad with the outcome. Far too many times guys want a big number then cry because the drivability of it sucks and that is where they spend 95% of their time with the setup.:thumb: