I picked up a pan gasket for a '54 235 at NAPA auto parts, and it doesn't fit my pan. The gasket is in two parts and symetrical. My pan needs a two-part gasket, but the left side has a bulge. Do I have a '54 pan, or was my '54 late enough that I got a '55 engine instead? The NAPA parts book had a gasket for something old up to '54, then one for '55, then one from '56-60something. Could I have the odd '55 engine in a '54?