why do you need to cut the floor with the 2x3? i made connectors for my car with 2x3 and i didn`t cut the floor. mine overlap the rear frame and i had to make an l shaped piece that i welded on to the "open end" of the beam to drop it down 1/2" and it cleared the floor. mine kind of look like this- http://www.bigblockdart.com/connectors/connectors.htm