Timing Chain Cover crankshaft opening is the wrong size

Just for future info....the early cover started in 1959 and was used up until early 1968 in poly 318's, LA 318's, 273's and 340's. They used a bolt-on timing mark that bolted to the lower water pump bolts and was ignition timed on the passenger side (for LHD cars :lol:) Late in '68 and in '69 they cast the timing mark into the cover. They still used the same early balancer and timed from the same side. These '69 and older engines used the cast iron water pump. In 1970 everything switched over to the driver's side and an aluminum water pump is used. The timing mark is cast into that side and the timing slot on the balancer was changed to match. The balancer still used the staggered bolt pattern for the crank pulley like the earlier models, but the pulley offsets were different. In '72 the crank pulley bolt pattern became symmetrical, but, everything else stayed the same until 1978 when they redesigned the cover to allow the seal to be installed from the front instead of the back like all earlier models. There were replacement covers (even from Mother Mopar) that had various combined features. I have one cover without the cast-in timing mark that has the '78 up seal design. You can usually tell if it's a replacement cover or not by the date code cast into the cover. When swapping covers and water pumps between '69-earlier and '70-newer, all the brackets and pulleys are different. So is the lower water inlet and corresponding radiator connection. Balancers can usually be swapped (on internally balanced engines) if you remark the timing slot and/or egg out one of the pulley bolt holes as necessary. Cast crank 340 and 360 engines need to use their correct balancer, a weight kit needs to be installed, or a complete engine rebalance to swap internal and external balancers.