Gimbal Housing 65532-s Modification v6 to V8

[jones01m]

Folks, I posed this question over in the restoration section but thought it may be better to follow through here. I have a gimbal housing that clearly has come out of a 4 or 6 cylinder. This is an MC1. The bottom ports where housing mates to y-pipe are blocked off. I see this is normal for non-V8. The casting looks like it is exactly the same as V8. I assume there is a modification that can be done to have bottom exhaust ports go through.

Question 1: Has anyone made this modification?
Question 2: If not, would anyone have pictures they could share of a V8 housing? An 898 or 228 sterndrive is probably the correct housing.

I will post details of this modification if someone could help me out to understand what the end result looks like.

thank you in advance

 

[Bondo]

Ayuh,..... I suggest ya find a later model transom housin',.....

What exactly is yer project,..??

 

[jones01m]

Bondo, the project is a 1976 Century complete restoration. Should have went with Chevy power plant for outdrive flexibility, but the power plant is Ford. This limits me to the "pre-alpha" gimbal assembly due to the inner transom plate motor mount width. I had a worn out spline-spline type steering from approximately 1975, and the assembly shown in the video I believe is in 1977-1982 vintage. Everything fits, it just seams the holes i mentioned are the only thing that is different from v6 to v8. I have looked at numerous images on the internet of the Gimbal Housing but find no visible differences between v6 and v8. I did not find a good image showing those bottom exhaust holes and how they intersect on the V8...

I appreciate the help. I am sure there is someone with a v8 mercuiser in 1977-1982 vintage that has this answer, or just a detailed picture of how these holes exhaust.

 

[Scott Danforth]

the ford stuff is ford specific when it comes to the transom shield and I believe the u-joint shaft.

so your ford power plant limits you to ford specific MC components.... or..

you could simply use a GM based A1G2 drive, one of these adapters https://www.summitracing.com/parts/...kUxgyY5MV4PDCvowFWn2wjlO1y3jVxGxoCXUQQAvD_BwE

and a custom coupler. you would have to use late model Volvo exhaust manifolds and custom make elbows.

 

[Bondo]

This limits me to the "pre-alpha" gimbal assembly due to the inner transom plate motor mount width.

Ayuh,...... I ain't done this,..... But,.....
I believe the inner transom plate, the rear motor mounts, can be used with later transom housin's,.....

Never seen a housin' with the idle relief ports on the inside, 'n not outside,.....
Seems it'd be a water pocket to freeze, 'n bust in the winter,....

 

[jones01m]

Gentlemen,

I appreciate the suggestions. A clue in terminology was given above: "idle relief ports". I had never heard of this previously. An internet search on this term, MC1, and v8, indicated that the difference between v8 and 6 was a variant in the part number: V8 - 70862a1 and 4/6 - 70861a1. It turns out that someone out there has performed this modification and a picture was available. Looking through multiple images I was able to verify the modification on the 70862a1 part. There are actually 2 idle relief ports and it is almost impossible to find on the images since the views never show both at same time. So the image below shows my findings.

Relief port #1 intersects the main exhaust hole

Relief port #2 intersects the bottom two holes for the v8 application

 

[iand464]

A newer gimbal housing will work. The Big hole in the transom need to be cut out a little and the middle holes move a little. You have to use the inner plate from a 78-82 with the wider engine mounts. Also you have to close up one of the bolt holes in the exhaust y pipe. It’s worth it though to get trim senders on the side and a square steering shaft. I did it last year. I have a 73 boat with an alpha transom and drive and a ford motor. I switched all the trim components for the alpha stuff.

I looked at my old one and those idle relief ports go out the side. It was for a v8.

 

[jones01m]

The feedback is very much appreciated. I went ahead and made the modifications. Final drill size was 9/16". There is much material at this locations, however it was very soft and super easy to drill by hand.

 

[Bondo]

however it was very soft and super easy to drill by hand.

Ayuh,..... Because it's Aluminum,...