FHM2 - With all due respect, the only ways you'll "find" a 276" CID flathead are 1) get a 255" Merc engine and bore it 1/8" or 2) get a 239" Ford engine (the most common), install a 4" Merc. crank and bore it 1/8". It's a lot of detail specific work but worth the effort. A lot of guys like a 258" engine - a 239 with the stock crank, bored 1/8". Getting the engine balanced will give you a much better running and longer lasting rig. FWIW