I`ve got two laying on the bench. I ran deadhead systems for yrs, w/ that pump, on 5 diff hotrods, and tried ( because of friends advise) a hi pressure return set up on a hot 406 sbc engine I raced a little, it made NO diff. Its all in how u set it up w/ full flow fittings and no restriction in the line or anything. An engine can get big and hot enough to need the bigger set up tho.