Im sure what you are feeling is the springs, in the clutch, absorbing alot of the blow. But Im sure with some slicks and spray you'll be damn close to 10 sec territory.
Do you know how much the truck weighed before weight reduction? Ever get the truck dynoed to know what your base line was? Just for comparison after all is done.
TBH it sounds like you need to work on your form. Learn to push your knees out!! You are most likely leaning too far forward. Arch you back like you should benching. Looking up at the ceiling helped me. And before you resort to chalk try the hook grip.
UPC 220lb Raw.
MINERIGGER, I have a buddy who almost broke the state record bench @245lb Raw, Fitcon. The SlingShot by Mark and pause reps is what he says will get anyones bench up.