I have the F7 sp and it pulls hard to 85 mph then fades fast with 92 for top speed. I'm not sure about my belt deflection, I took a 60 thou shim out to get the belt to set up on the secondary clutch like my dealer told me. This is the only thing I have touched. ( All the service bullitins are done ). I drew a black line up the drive clutch and there is 1/2 an inch left. Also the tach says 8100 rpms, so I put some heavier wieghts in and then saw 7860 but still 92 mph. The sled runs great, plugs look good and compresion is 150 on both sides. A little over 300 miles on sled. Any help would be greatly appreciated.