It's bad enough to butcher any truck but we restored a 57 CAMEO that had a 383 mopar engine whose right exhaust manifold wouldn't clear the firewall so they just cut a foot square clearance area out and left it open. On the inside the floor shift lever was a right angle lug wrench welded to the stub of the original and to do a tidy radio installation they cut the whole center out of the dash and welded in the same size piece out of some ford but, we had to admit the radio exactly fit the hole. Best of all--we took pictures before and after.