Pre alpha MC1 - lower exhaust holes?

[HRK]

Must be losing my mind. Have a 3.0 TKS crate motor coming to replace my '80 2.5L 120hp motor. I know the new style exhaust is different, but for the life of me I can't remember what bolted onto the two small holes under my exhaust on the transom.

I attached a photo of the transom assembly and my exhaust. My exhaust only covers the oval exhaust port on the transom assembly, not the two bottom holes like the new style does. Can anyone tell me what goes over those two small holes, if anything?

EDIT Can't seem to upload from my phone, will post the photos later at home.

 

[Scott Danforth]

decrease your image size to about 400k. your phone is most likely taking a 2meg or larger pic

 

[alldodge]

what bolted onto the two small holes under my exhaust on the transom.

The transom is the same for the 4, 6 and 8 cylinder, just different pipes. The 4 and 6 don't use all the holes available.

 

[HRK]

Ok, got the photos uploaded.

 

[HRK]

The transom is the same for the 4, 6 and 8 cylinder, just different pipes. The 4 and 6 don't use all the holes available.

Ah, that makes sense. So I'm not crazy, I couldn't figure out why I didn't remember taking anything out of there. So they just stay open then. Thanks!

 

[alldodge]

I'm finding that pipe and its just installed leaving the lower holes open, but have your same concern. Looked thru the engine manual and drive manual and they both show the same thing. The V8 and other inline 4 and 6 cylinder also show others which cover the holes. Wonder if the first years had knock outs which were punched out when other exhaust was used. I don't know maybe someone else like Bondo might

 

[arabian 200]

The last one I did had a different exhaust tube that matched the transom Assy.The two smaller holes have o rings just like the big one,the smaller holes are for the exhaust relief holes in the gimbal housing

 

[bbook83]

I posted on this a couple of years ago: https://forums.iboats.com/forum/eng.../10167095-exhaust-pipe-on-1974-140-mercruiser

I think even Bondo was stumped then. The bottom holes are not exhaust relief. Those are in the large oval exhaust port. They are total dead ends with no apparent purpose other than may being cast for multiple applications.

 

[alldodge]

The same year motor also show this kind of exhaust tube

 

[arabian 200]

II-Think it is easy to find out,put a garden hose up to it and see where it goes when water is turned on