i have f150's too. i mounted them short side forward for a few reasons, one axle wrap less spring in the front, two the front mount would have been where the front on the bed was long side forward and would probably get caught a lot, three i have no plans on bobbing my bed it still gets used as a truck to go camping hunting, etc...
i have 3 leafs plus overload with 6 inch shackles and get 12 inches on vertical travel. i was using a two post lift my friends dad has in his shop and measured from the spring plates to bumps with the suspension fully drooped. this past week built new mounts and installed my 10inch fox which i thought were going to be long enough because of angling them inward but they stop my droop about approx 1.5. i will get some 12's one day.
i know jrock has a similar setup maybe he will agree. im theory is that the ass ends of our trucks dont have enough weight to fully flex the springs. my example when i used a forklift to check for bumpstop height etc... i lifted a front tire up and got 26 inches under the tire before the rear tire lifted, then i lifted a rear tire up and got 31 inches under the tire before steering links hit frame. both front tires were still touching though. this is with ruf and 35 inch km2's. im guessing anyone with toy axles has encountered this. the toyota rear axles are just light. obviously the bigger the tire the weight it will have to pull down. the reason i didnt know the 10's werent long enough was because i never had the suspension fully drooped with the tires on until i had it on a two post lift. for comparison the front has 8 inch of vertical travel from tierod to oil pan but while flexing on he forklift it uses 11inches of shock travel for full flex. also has to due with shock mounted outside of the frame/bumpstops and not inside like the rear.
hopefully this makes sense. im sure other people have made the same observations. but im happy with my flex.
