I have built a 283 in a restoration project of my 1966 el camino. I like crane cams and used their 266 adv grind. It is a 212/ 212 @50. I don't have it running yet but will let you know how it does. I have an oem balancer that I ordered from summit and the pulleys dont match up. it looks like I will have to try to find the stock balancer for an early 283/ 327. good luck