franko64

I've got a question... On a small block chevy, the older oil pans used a thinner front seal than the newer ones. Was their a corresponding difference in the timing cover? In other words, were the timing covers different for the thick seal oil pans than for the thin seal oil pans?

DZAUTO

No. Only the pan itself, 56-74 (thin) and 74-later (thick). If you don't know what vintage a pan is, you just have to measure (or use the 2 front seals to make a comparison at the gap). Many pan gasket sets come with one of each front seal and instructions for determining which seal to use with the pan which you have. I didn't include the 55 pan because it uses a totally different gasket set (although the front seal is the same as 56-74). A 55 pan is different because the 55 block did not have an oil filter pad, thus the left rear corner of a 55 pan is a different shape.

JohnZ

Just to confuse it further, service replacement oil pans for pre-'75 cars don't use the original thin (0.22") front seal - they're designed to use the later thick (0.41") front seal (which is packaged with the pre-'75 service pans). If you're not sure which pan you've got (original vs. service replacement), flip the pan upside down on a flat surface (without the gaskets) and measure the radius of the front seal surface from the center of the opening down to the bench top; if it measures 2-1/4", it takes the original "thin" (0.22") seal. If it measures 2-3/8", it takes the later "thick" (0.41") seal.
:cheers:

franko64

Thanks. That clarifies things. That's kind of what I thought, but I was reading a book which made it sound as if the pan and cover were a matching set together. I think the book was just worded kind of funny.

DZAUTO

John's added info is 100% on the money! I failed to mention the part about replacement pans.