360 magnum. 1 piston lower in cylinder??

Well the KB 107's would be the closest. Weight is close enough to be within factory balance tolerance, and with the flat top and the compression height and a .039" head gasket, with 62 cc Magnum head combustion chambers and a .039" thick head gasket will be around 10.6 SCR; with a .050" thick head gasket, it'll be around 10.3 SCR. (Those pistons will stick out a few thousandths from a Magnum block...)

Now if you are using the EQ's IIRC the chambers are 62 cc's and so you are in the same CR range.