So i found a couple that are like the "older style" with the bolts around the circumference. Now the two im looking at are not much different in price but one delivers 80gph free flow rate at 5.7-8 psi and the other delivers 110gph free flow rate at 6.5-8 psi. Now giving my previous information on how my truck is driven and how often and what rpms and such and fully loaded weight at 24,000lbs max what pump would better suit my needs? I have pretty hilly terrain in my area if that matters....

What does the free flow rate even mean? I personally feel the lower flow rating would be better giving im not a racecar and i already have good fuel flow thanks to gravity but your guys' input makes me feel much better about making a decision Haha.