273 commando Build

As I mentioned earlier, I don't believe steel shim small block gaskets have been made for decades. Here's Summit's list of head gaskets. There is 1 with a .038 compressed thickness and many with a .039 and .040 compressed thickness. They are also listed for bore size and you will want to get as small as you can and still stay thin. The bore sizes are designed to fit 318-340-360 bores. The only other option is to contact Cometic and have them make a small bore MLS (multi layer steel) gasket. They aren't necessarily thin though like the old steel shim's were. (usually around .020)

DODGE 4.5L/273 MOPAR SMALL BLOCK LA Head Gaskets