Trying to decide which loader to try next to see if I pick anything up. Boat is a 1972 18ft cobra jet 500 HP 454 with berk 12JG. Pump has old jetovator, 4 degree wedge, aluminum B impeller, SE sport loader. With Accurate GPS it will do 70 MPH. I am looking at either trying    The SS loader or maybe even the more aggressive one. Do any of you more experienced jet boater think I will have any gains or am I going in the right direction? When the fund approve I will install a stuffer and inducer and see how the boat performance if I want more I will buy a place diverted so I can run a nozzle insert and droop.

Just bought a  18ft semi V boat the other day and finally got the mpg. It is a 12jg berkley with B impellar, 4 degrees wedge and jetavator with se loader. With 3 grown men, ice chest and 20 gallons of fuel in the tank (tank in  the bow of boat) I gps it at 62mph it had a little left but not much. But I pulled 5800rpm and then 6000rpm after losing passengers but didn't get a GPS reading that time. My question is should I try out an A or AB impellar or go with a ss loader to see were that gets me before I spend the money on a impellar. I want to GPS 70mph.
Motor was just assembled mild 454
9:1 CP
540 lift 238 248 D @ .050 114 LBSP
049 larger ovals small port work 3 angle valve job
Weiand high rise tunnel ram with 2 600 carter competition
Howard roller rockers 1.7 ratio
Msd ignition with 6AL box
Cam operation rpm is 3000 to 6000.