musclecargt500,
It appears you have a FT (truck) block. That is not necessarily a bad thing, you just need to get a bushing to put in the distributor hole. The truck engines used a larger
oil pump drive shaft, forcing the distributor shaft to be larger as well. They also had larger diameter crankshaft noses and thicker flywheel flanges (no effect on your build either way). These beefier parts helped them endure the stress of getting a big truck moving.
Anyway, there are truck blocks out there that look exactly like CJ blocks. I have seen them with the "C" on the back, with webbing, CJ date codes..... they look exactly like a CJ block EXCEPT they have the tell-tale large distributor hole.
Fortunately, your problem can be solved as easily as a trip to your local Ford dealership. Believe it or not, they can get you a bushing for this application. They cost around $15 to $20 depending on if they have to get one shipped in from another dealer or warehouse. Also try DSCmotorsport.com - I think he sells them too.
Be careful when installing the bushing, it has an
oil hole in it that must line up with the passage in the block. Also be sure to put some loctite on it or it could spin in the block later.
Again, don't let this scare you about your block, it is most likely a good block - it just happened to live in a big truck engine bay. Look at it like this - it's probably never even seen 5000 RPM and you essentially have a "new" standard bore 428 block because it truly is sitting on a newly finished bore at 4.13"