I had one that Dick Landy built in the 90's pump gas 440 block 496" made 660hp and ran 10.50's in a 69 Road Runner . It was a very expensive build at the time and likely about the same cost as building with a regular hemi block. The heads flow alot of air and they look cool. If you had an industrial 413 block , 440 crank , you could use a standard 426 piston for a relatively cheap build.