Where can I buy a reliable remanufactured 318 for 1971 Duster?

am i reading this correctly in that you replaced the pistons and didn't balance the rotating assembly?
Yep that is correct. I used a factory refurbished crank and weighed the original pistons and rod on the big and little ends and matched the new pistons as close as possible to those weights. They was off a couple grams. The 360 is external balanced the harmonic dampner and flex plate is where the balance is at. It was not rebalanced at a machine shop. It is a street car built for mild performance on the street it's not a race car turning 7 grand consistently. I feel like alot of people get stuff in there head that something will not work when it absolutely will. My engine has been running for 4 years now I haven't had any issue with the balance or vibration. And it turns 6 grand no problem. I would not pay to have a street engine balanced especially an external balanced engine. A internal balanced stroker maybe.