(Best) copper head gasket and offenhauser aluminum heads

[Ronnieroadster]

Unfortunately the only gasket currently being made with water coolant holes that are not restrictive is made by Cometic. Every other brand available have those small restrictive holes in four to five of the most critical areas.
Some brands of older gaskets made a long time ago came with coolant holes that were less restrictive. Swap meets like Hershey as an example would be a good source to find sets of these older gaskets.

Other than that it is possible to open up the water coolant holes in composition or copper head gaskets as needed in any new set of gaskets currently available if you take your time. Its worth the effort.
Ronnieroadster