Looking for a 318, 340 or 360 smallblock

Hello Cuda Guy,
Heres a thought, I have a 1967 273 Super Commando Motor out of a Barracuda that was rebuilt before i got it in my 1972 Duster. The motor runs good with one little problem, it has blow by. I havent done anything to try and figure out why but i do know that I am getting ready to get a fresh built 340 motor right after christmas, so I will be removing the motor soon. I will most likey remove some of the parts for that motor like valve covers, intake, and starter and alternator, but I would willing to work with you also, I am not sure what it is worth but call me and we can talk more, I live in Howell Michigan not to far from you, i can send vidoe of motor running and any picture you want.