So, I have a 48 Plymouth coupe sitting here still housing the original flathead 6. The firewall is not flat on them, around the back of the 6 the firewall has an offset towards the passenger compartment that is about 3" deep and about 12" wide. From the non-off set firewall, to the front of the fan blades is 28", as i remember, the fans run real close to the rad. The inner fenders are 22" at the narrowest point, (they are wide at the top and get narrow about 1/2 way to the frame, front to back on both sides) and the steering column sits under the narrow part of the driver side inner fender. The inner fenders can be moved and the steering column can be changed with a steering box upgrade, but the length will require some serious adjustments. Gene