I did not try JB weld, it is good stuff, the problem with it is aluminum is pourus, I was pretty much unsuccesful in welding because of the oil in the metal. however enough metal adheared so it could be sealed with the Permatex product called "The Right Stuff" that stuff will seal anything.
Try the JB and let us know if it holds up, to use the 28 pan you have to add material to the top and bottom of the block (or the pan) and then file/machine it flat. The key here is to get the aluminum as clean as possible. I even tried baking it for two days in a welding rod warmer, did not help, the weld was not that pretty.
Will the flywheel fit-yes, however beware of the AVS with the coil offset to the the cylinder bore, be warned this advances the timing and will require the hub for the later AVS. ALWAYS use a timing light when setting the timing on these engines.
