I have a P360 with 28" silvebacks that bogs in high range and in low range just not as bad on the smallest of hills and sometimes flat land. I have Pink primary and Red secondary springs. My check belt light is on also . Called my buddy up on the phone he said it sound to him like its the belt from how I explained it to him.. Need some feedback here guys. By the way the carb is clean with a #155 jet.