MD water header

I removed the rear water header cover plate to replace the gasket. Stupid me, I didn't pay attention to which way the water header (attached to the plate) is supposed to fit. It has a larger opening on one side and a smaller opening on the other. Can someone help as to which was it's supposed to go? I don't want to reinstall it incorrectly. Thank you.

Sorry, gave out wrong information. The header is open on each end and on top (or bottom). I believe it makes sense to have the open side facing down, but I am not sure. Just need clarification on this.

On the W9 and WD9 the openings are to the top. I imagine it's to direct the coolant to the warmest part of the sleeves and upward into the head.

If you have the ones with a short header that will work in the front or rear hole, the opening goes down. If you have the long header type. Front and rear will be different, long ends go toward center and openings down.

Sorry Bruce, here I thought I was being helpfull. Obviously someone got them in backwards and Murphys Law said I had to get two engines like that. Even more strange is that one was a gas engine the other a diesel. I don't know if they are short or long because they are all the same.

D Slater; what is the difference between a short header and a long one? How can I tell them apart? At what point in their manufacture did they change? My diesel engine is a 1952 and the gas is a 1948. I may as well go for whatever was the better style when I reassemble the engines.

Thanks,
Dave

Diesel short water header on the back of cover is shorter than the outside of cover. Front and back cover will work in both holes. One type of long header cover looks like the short header on the outside, but the header on the inside of cover is about 2 inches longer than the cover on one end. For that type the front cover long end goes to rear of block. Long end on rear cover goes to front of block. Not sure but think the long type started in late 1952 or in 53. Some of those covers are a little different, like maybe 2 manufactures made the same part.
Starting in later 1956 a thick steel cover with a long header similar to the thin cover with the long header was put on the diesel engines. Those covers and the pevious cover were sold as replacements for the early cover at one time, depending on time of purchase. Replacement thick covers for early tractors were sold in a kit with different bolts and a crosshaft bracket to give more clearance for the thick covers. Can't remember if the bracket was included in the kit or purchased separate. IH thought the later covers were a improvment, although the thicker covers were just to help with rust out.
Gas engines use one long cover with water header, Most all have the word top stamped in them. Top goes to top side.

D Slater; Thanks for the info. However it raises another eyebrow. If the gas engine only has one cover then both of these engine blocks must be diesels. They were both stripped when I got them, i.e. no head, pistons, crank, etc. It was one of those you-gotta-take'em-both deals so I just loaded it up along with the other one and the pile of parts that came with them. That's a good thing I quess, because I really didn't want a gas block. The only pieces that were still attached to the blocks were the headers and I removed them to facilitate cleaning.

Oh well live and learn.

Thanks again.