Do yourself a favor, under no circumstances EVER buy a pro comp deal. I've had a couple CSR and decided I couldn't afford one for my small block, that was a moment of stupidity I regret every day. First, the backing plate was wrong, didn't line up at all for my 351W and had extra bolt holes to boot, only thing that saved me was I know a guy that owns a laser cutting shop so he could correct it by cutting me a new backing plate. Still cost me $30 though, after I got it mounted found out the pump housing ends leaked, so I had to put that in the mill and deck them straight, and now the pump itself is leaking where the pump motor seals up to the main part of the housing.
How I wish I would have just paid the extra $125 and bought the CSR or Mezeire to begin with.