Just use adapter plates. It ain't that hard. You can make them yourself with some 3/8 aluminum plate, a gasket and a countersink.

Bolt the to the head with a THIN coat of orange silicon and be done with it.

Thousands of engines have been used with adapter plates.

Just because you think it won't make it true. Horsepower is KING. To dispute this is stupid. C. Alston