R43TS?? Those won't work. The "TS" in the number means "taper seat". Thsoe plugs are for the '69 and later heads that use the tapered spark plug seat, intead of the gasket style plugs used on the older engines. What you'll want is the R43 gasket seat style. The taper seat style will not seal properly in the head, and will cause a compression leak.
