Trying to sqeeze more out of my 340

Are you sure the convertor flashes to 5200? Years ago I was running a $225.00 GER convertor in my Demon and everybody was telling me I need to buy a good convertor. I bought a $600.00 Coan 10in Race convertor and put it in the Demon and I slowed down over a tenth in the 60 ft. Now I want run anything but a PTC convertor.