Seadoodoc
Active Member
My personal opinion ( oh geez here comes the linch mob) build it with stock a pump. Fast furious and cheap. To put things in perspective here, stock 787 is a 140mm pump. Stock 951 is a 155mm. Now grab your calibers and measure out 15mm. So the pump is 7.5 mm all the way around outer diameter. Less than 1/4 inch all the way around. In our Superstock racing days (187 hp dynoed) we ran a 148mm Mag pump @ 68.4 mph on XPL. Thats 1/8 inch bigger. The task of mating up any bigger pump to an X4 is a daunting machine worked process. Reality is pump shoe is still 140 mm, so whats accomplished? With pump nozzle extension ( 95 XP) and a 148mm RXX Mag pump, some ridiculous machine work, hrs of welding and port matching, Im sure mine handles, accelerates, and will mph any stock 787 pump by 10%. Conclusion is worry about that mod when conversion is done and running. Imhop... and here come the dogs ! btw dip switches are MSD ign timing control. Secret to success for cheap power.