Im deciding that im going to be removing my std cab & installing a extended cab. Are the rear extended cab mount brackets that are welded/riveted to the frame sitting at the same height as the front cab brackets? Im aslo going to be extending my frame as I want to keep the long bed. This will be a long project due to time & funds. I know I can do it cause I converted my 76 F250 std cab into a Crew cab about 15 yrs ago & extended the frame on that as well.