I'm a little confused on the long/short water pump issue. On the front of my 261, there is a big round hole (maybe 4") with 3/8" holes surrounding it. The engine I got out of the scrap yard did not have a water pump on it, so I am unsure what it is supposed to have.
My 216 and 235 seem to share the same water pump, which bolts on towards the top of the block, if I recall correctly.
If someone had examples of short and long water pumps, I (for one) would appreciate some pictures.
