273 copper head gaskets SCE

I ran copper head gaskets with an o-ringed 273 block with a touch over 12.0 to 1 compression ratio. This was back in the late sixties and I got them from Ed Hamburger. He suggested o-ringing the block and running the copper gaskets because I was continually blowing the shim steel and composite gaskets. The reason was the SBM only has 10 head bolts per side.