Thanks Twostick, block says 340-6 so I think I'm ok, but I know what your saying! Here's the update, pulled the damper, casting number starts with a 40 which I think is for late 70' 360, it's the one that came on it Pulled the damper of my 70' steel crank 318, local Mopar scrap yard says same part number for 69' 340, cleaned it up, a splash of paint, on it went, motor is now smooooooth thanks to all for your help.