Projects 61 F100 cab bushings

I'm in the middle of a floor pan/cab support replacement on my 61 F100. After I replaced enough of the inner cab that I actually had something to mount the support too I went to test fit the support with bushings and think I have an issue. These are aftermarket bushings from Carolina Cl***ics, and don't appear to be the same style as the original, but do seem to be the standard replacement.

My issue is the top rubber bushings have a neck that looks like it fits inside the frame mount hole and then meets the bottom pad, with a steel sleeve running inside of both pieces. To make it fit correctly, I think I would have to enlarge the hole in the frame tab. The easier route would be to cut the bushing neck off, but would that allow the bottom rubber to collapse. If any of this makes sense I would love to hear your thoughts, especially if you have installed these before. TIA.

 

I don't recall that issue when I did mine, but it's been a long time ago. I'd be inclined to enlarge the hole and use the rubbers as designed

 

I did mine last fall....new cab mounts and floor, as I remember it the raised part went through the hole. I went to the shop and the rubber fit pretty much like the picture that should have came with the mounts shows. I'd agree with @RMR&C to just enlarge the hole.
It ain't always fun My 62 is a unibody....I replaced the entire torquebox as well as the lower rear part of the cab.

 

Thanks for the push to do it the right way. I found a step bit with a 1 1/8" OD at the biggest step so I just drilled through and was able to avoid any taper. The fronts will be easy because I can reach them from above, the rears may be a little trickier getting them from the bottom. But the bit is short enough I should still have room.