Re: 428 block ID
FE block casting numbers of the 428 CJ era will be found on the front passenger side of the block, if present. Casting numbers on FE and FT (Ford Truck) cylinder blocks since 1966 no longer indicated the type of block, but became a leftover formality from earlier days when the foundry had far fewer block variations. As the decade closed, the Dearborn Iron Foundry and Cleveland Foundry would stop placing these deceptive casting numbers on new engine block patterns. The casting numbers would return when the new Michigan Casting Center started producing FE and FT blocks in the early '70s. MCC blocks would not contain the familiar "352" marking of years past, but would instead use "105" as a general identifier. The picture above shows a CJ block that lacks casting numbers. Casting numbers that appear frequently during the CJ era include C6ME, C6ME-A, C7ME, C7ME-A, and C8ME, but beware -- these markings do not indicate a specific block whatsoever, since any FE or FT block of the period can be found with any of these numbers.
Some blocks have a "428" cast onto the floor inside the water jacket. There are two common positions to view this protruding number: one is just inside the center freeze plug hole, the other is directly beneath the long coolant slot at the rear of the block. If present, you can be sure the cylinders are thick enough to support 428 pistons, core shift permitting. If the number is not visible from either position, you'll need to make other verification checks. Measuring the gap between cylinders using a drill bit is the easiest way to determine whether your block is capable of supporting 428-sized cylinders. It is presently thought that if the shank of a 15/64" drill bit will NOT fit between the cylinders at any reachable spot in the six core holes, the cylinder will likely handle a 428 bore, core shift permitting