Yeah getting it high enough with a 4'' lift already being on it was interesting. That's why I recommend high lift jack stands and 4x4 wood blocks on hand. Or even some thick wood plans to put the stands on. Really glad I had some of those laying around.

 

Looks like a long leaf. Just might take out my 3" block, reinstall the stock 1 1/4", and put this in. Just might remove my airbags as well, if this prevents the rear sag from simply hooking my 7K enclosed tandem. Crap, with these trucks, a grocery shopping spree will make them sag! LOL

 

I remember when my 97 Silverado had 3 leafs from the factory. Now the F150 and Silverado only have 2.

Unless you use the vehicle for commercial use, the payload rating isn't really relevant unless you are grossly overweight.

 

Not sure if this helps you, but I gained close to 2.5" with the AAL. I ended up pulling my stock 1.25" block and this is how it sits with a 2" AS level in the front. The rear sits just a bit higher than the front now.



I would think with your topper that leaving in the 1.25" block would be pretty darn good. I loaded up 500 lbs worth of wood last weekend and it sat perfectly level. I'm glad I wen this route instead of air bags like I did on the last truck.

 

Came close to air bags. And even basic Air Lift kits aren't that much more. But I would have definitely paid a shop to do it then so that's added cost. I also don't currently tow.

 

Looks good!
That might just work for me, even with the cap off. The cap weighs right about 200#, and I do want to maintain a little tail high attitude.
As it is, I have to put about 8-10# of air in my bags to maintain the rake I've got when I hook that trailer.