I had a 48 willys and cut my floor out and fab'din a CJ floor and firewall. I was able to use CJ seats and the higher center floor aloud for my T176 tranny,>firewall alouded for my CJ steering/clutch/brake pedals(hanger). I had a bit more leg room as well. I have some pics if your interested. I used a 75CJ5 frame and streched in front of the tub 9 inchs. I ran a AMC401/T176.
goodluck on your willys