I have a '64 L-76 327 in my Vette. When I mock up the oil pan gasket with the thin front seal I can slip a .020 feeler gage between the seal and the pan easily with just the weight of the pan (not bolted down). My concern is I won't be compressing the seal very much when I bolt down the pan. I believe this application calls for the thin seal. I am using a NOS L76 Pan with an aftermarket chrome timing cover. Could the timing cover be causing the problem? Should I just use a thick seal?