Beg your parden BUB, but 6 1/8" WILL fit, with a different specially cast Block..
Stop "Thinking" you are a hot-shot and get OFF your High-Horse (pony)..
Open your eyes and look, several are and have been pulling in Ohio and Carolina for several years.
The one here in Plain City, Ohio is only 5 3/4" Bore, but can be bored to 6 1/8" also..
Facts is Facts, warp them any way you please.