Cadee,
Installed an aftermarket rear splash panel on my '49 3100 Chevrolet. Had to remove the rear bumper and adjust the bumper brackets down about 3/8 inch. Install the splash panel with the bumper brackets slightly loose. After you get the splash panel installed ( be careful with the sides of the splash panel so they don't scratch your fenders.) I put a couple of coats of masking tape on them to prevent the scratching. Tighten up the bumper brackets and install the rear bumper. Patience and several attempts at getting the adjustment correct is the key to it fitting correct.
Hope this helps.
Tim
