Ford Falcon Early V-8 Engine Mounts
The 221 and 260 Engine blocks are virtually identical except for 2 issues. Different castings were used for the different bore sizes. Since they are of a "thin wall" design, the 221 can not be bored out for fitment of the 260 pistons just like the 289 can not be bored out for fitment of the 302 pistons.
The most perplexing difference between these blocks is the spacing of the engine mount bosses. The 221 is generally considered to be an early casting and the 260 is considered to be the later casting. On the early engine blocks the mount bosses were spaced at 6 inches apart and on the later engine blocks the bosses are spaced at 7 inches apart.
This information would lead some to believe that all 221 engines used a 6 inch spacing and all 260 engines used the 7 inch spacing. Of course, as with most things during this period, this is not true and you may find a 221 with the later 7 inch spacing and a 260 with a 6 inch spacing.
If you are too lazy to measure the spacing, just look at the freeze plugs, those engine blocks with 6 inch spacing will have 2 freeze plugs on each side and those engine blocks with 7 inch spacing will have 3 freeze plugs on each side.
Since the 6 inch spacing was used for such a short period of time, the aftermarket has never had a large inventory of the correct rubber mounts and all were virtually sold off. However, since the 7 inch spacing is still used today, numerous aftermarket suppliers can provide the correct mounts.
Bottom Line: Do not rebuild a 221 unless you have a source for the mounts because you can not put the pistons in a different block unless you can find a 221 block with the later 7 inch spacing. An almost impossible task.
If you choose to rebuild a 260, check the block and make certain you use one with 7 inch spacing. Almost all 260 blocks used this spacing.
Identifying by Casting Numbers:
The casting number on a 221 engine block is located at the rear of the block UNDER the intake manifold.
The casting number on a 260 engine block is located under the right cylinder bank at the rear.
- C2OE-6069-A, B, C, D OR E