Not sure what roll out value that is? Is the Inches? or mm?
One of three things is wrong:
-battery back gone south
-gearing is way off(what are others running?)
-motor is crap although it would be crappy right from the start so this is unlikely your problem.
Sometimes gearing can be tricky, if u have a heavy finger you may not be able to gear the same way a smooth conservative fingered driver does.
with GP3300s you should not be dumping in any stock class. We run stock rubber and 19Tfoam and gear to our hearts delite without dumping.
"Without Rules its just Backyard Bashing!"