Addendum 19 Dec 08:
Here are pictures of a Moss Motors (USA) supplied rocker panel, right side only. (Photos supplied by Lamar Carver in Fayetteville, GA). This is the part that is too tall on the outside curved surface, same as parts I bought in 1977. I don't know the purchase date for this one, but I believe fairly recent. These panels were "fixed" by Eclectic Motorworks in Holland, MI. Solution for this too-tall rocker panel is to flatten and re-form the bottom flange with the bend line a little higher and trim the flange again.

In these pictures you can see where the original bend line was in relation to the new bend, as the original line is still visible below the new bend. At rear end (left photo) the bend is moved up about 1/2-inch. At front end (right photo) the bend is moved up about 5/16-inch. The rear of the rocker panel and the rear fender need to be raised about 1/8-inch to be flush at bottom of the body sill. The flange was trimmed a bit too narrow at front after reforming, but this is no problem since the lower body trim strip will hide it.

Addendum December 1, 2010:
These photos and notes were supplied by Gordon Fletcher, near Denver, Colorado). The first picture is an original issue rocker panel removed from his car, as it has the original paint (Tyrolite) and the spot welds had not been tampered. Gap at right side of front edge is about 3/8”, and overall width is just shy of 3-3/4"


Next is new rocker panel form Moss Motors. Gap is 1/8”, approx 1/4” less gap which prevents abutting the piece to the inner sill. Outer edge is 3-3/8”. (overall 1/4” narrower than original).


The small box pasted into the photo below shows where material could be removed, but the outer portion (outer edge) is still about ¼” shorter than the original outer part (doesn’t show true due to the camera angle) and might not meet the front wing as it should, i.e. gap.

I had exactly these same problems with rocker panels I bought from Moss Motors in 1977, so I presume they are still selling the same misfit parts. In my case, for my first installation, I did notice the too-tall outer surface. My solution at that time was to modify the dogleg on rear fender to match height of the new rocker panel. That turned out to be a big mistake, as the doors were then difficult to fit, touched top of rockers, and would pop the latch with any significant bump in the road. That can be very irritating with some roads that I travel.

Loggiing road in Oregon - - - Rope holding the door closed.
The better solution is what Lamar Carver shows at top of page.

For the top surface being too narrow, I did exactly what Gordon Fletcher shows in his third picture, just ground a little material away at the outer notch to make it fit. Gordon is correct in that this makes the rocker panel sit about 1/4-inch shy of the intended outboard location. That in turn makes it difficult to push the front fender inward enough to align with the rocker panel, then leaving an unsightly gap between rocker and fender.

I remember what I did for assembly. I shielded the lower part of the fender with a blanket, placed a wide board against the lower fender, used a pair of large C-clamps to pull the board inward while I jacked up the board with a hydraulic floor jack. This effectively pushes the lower fender inward while raising the rest of the fender upward. There is a limit to how far this will go, as the vertical line of bolts inside the cockpit still has to go through holes in the inner body, and the top of the fender will protrude above the door top. But then with the too-tall rocker panels the door will be adjusted to the highest point of possible range for the hinges and latches, so the door top may come out somewhere close to the front fender top. When all was done, the top front edge of the door hit the body top cowl and chipped paint.

Again I can say, the first solution at top of page is somewhat bettter. But better still, if you back up one page you will see that last time around I used different rocker panels that fit MUCH better to begin with, not much fiddling required, and very nice results in body alignment.