I have a 360 VBP spring in my '72, street driven quickly for some 15 years, it's taken some shots in that time period.....
I know from the frame measurements to pavement, that it's at stock ride height in spite of the 460 springs in the front....makes me wonder if they are seated right, but too much going on to be concerned now.....
I have had KYBs on there, now Bilsteins.....and stock rubber bumpers, I really need them badly as my tires on full upstroke will compress the bumpers a good bit and have maybe 3/8 inch to the fender....oops....so YMMV with shaving them to a trap shape....I would not....
I don't think much of cutting out the frame bottom Murphy and his laws...probably have to reinforce something, weld bottom seam at least in that area, maybe....:crap::beer: