I own 2 67's one a 100 the other a 200 . Both have poly's .The 100 has a factory harmonic balancer the 200 does not . They used 2 different cranks . I found with research that the cars and 100's got balancers and the 200's and heavier trucks did not .Do to factory thinking on RPM's. And a 360 crank will fit a poly with machining .Distributor ,h2o pump ,oil pump, fuel pump will fit the "L" from The "LA" .Nothing else will fit. I would get a hub machined to fit your crank snout . That should not be hard to get a machine shop to make . Then use the bolt pattern for the LA 2 groove pully . I would not put a balancer on an engine that does not have one . I have owned these engines for years . They are misunderstood by most Mopar people . THey are very good engines.Made on a 70 degree angle not at 90 like most engines . that's why they are so wide . But it gives them a lot of torque . And for everyday driving torque is the important number not the HP#. Leave your un balanced engine that way . And yes in closing they came with out a harmonic balancer sometimes. Hope I was able to help.