Weld brackets and be done with it...The muffler shop will do it for you for $50 or so...I like the idea of the onboard air tank.

 

You need to just drill and tap the holes and call it a day

Also frames should never be heated or weld on in less it's stated in the manufactures repair guide , also welding on a fully boxed frame you won't be able treat the inside for rust

 

Same goes for drilling holes....

 

Agreed, DO NOT weld or drill holes into your frame. Doesnt everybody understand how important a good frame is?? Why do you think frame damage totals a car pretty much all the time? Think about it

 

I don't think the Chassis Grabber is made for 1/2 tons... Lots of talk about Class 8 truck frames.

 

Billy Mays would 'Super Putty' that bad boy on there. (I wouldn't tho)

 

Could you not simply mount the the bottom side of the bed or a cab support? While I'm sure drilling holes could be fine and welding could be fine, why risk it? Have a fab shop engineer some straps that will reach existing frame mount points or go through the bed floor. Just MHO..

 

Ok
What I would do is fabricate a secondary bracket that lines up with factory holes on the frame and can be welded to the tank. No new holes in frame. no heat on frame. no rust on frame. Can than locate tank almost anywhere. May cost you more but then no worries no concerns. no warranty isuues.

 

Maybe try to find some large enough u-bolts that will go around the frame rails, or make it with a piece of steel and long bolts. Bolt the tank brackets to it.

 

Here's Larryw1's setup: https://www.f150forum.com/f4/install...-system-56660/

I wouldn't be that worried about a couple small holes in your frame.