The L22 series inline 6 will require modifications to fit in an earlier engine bay, due to the different motor mount locations, but it is NOT larger than the 216/235/261 engines. It is actually a fair bit shorter in both height and length, and quite a bit lighter. The exact specs are in Santucci's Inline 6 Power Manual, but I don't have my copy handy at the moment.
The only thing larger in the L22 is the main bearing count - 7 vs. 4 in the earlier engines.
