What could account for these Exh Boot differences?

[Boomyal]

Below are pictured two different exhaust boot shapes. The first one is the shape of the boot pictured in my factory manual.

The second is the shape of the boot that I actually have. This is on a '76 Merc 888. Could this mean that there might have been a manifold/risor change somewhere along the line? Or could this just be a normal OEM variation that the manual did not bother to depict. (my manual is not a parts manual, but a service manual)

 

[Bondo]

Re: What could account for these Exh Boot differences?

I'm just Guessing here,.......
But,.....
I believe that there have been both 3",+ 4" risers used over the years/ Models.......
1 Appears to be a 4" straight thru,+the other is a 3" to 4" isn't it,..??.....

 

[Capt Ken]

Re: What could account for these Exh Boot differences?

The boot in the first picture is for a later model that has four inch center mount risers. The bottom picture is for three inch rear mounted risers which was standard on the 888.

 

[Boomyal]

Re: What could account for these Exh Boot differences?

I'm just Guessing here,.......
But,.....
I believe that there have been both 3",+ 4" risers used over the years/ Models.......
1 Appears to be a 4" straight thru,+the other is a 3" to 4" isn't it,..??.....

Yeah Bond-o, it's a 3 to 4".
Here is a picture out of my manual. It is but one of several depictions of 'da boot'. In another one, it actually shows a parts breakdown including the mani's,
rear mounted risors, down tubes, etc. They all depict the 4" straight thru style.

 

[Bondo]

Re: What could account for these Exh Boot differences?

Ayuh,......
I just went out,+ Looked again,..... This 1 is also 3" outlets on the risers.....

I also measured the Intake, it's 9.1/4" between the bolts, C to C......

And,.. I pulled this Bracket we've been talking about,...
My 1st guess is,..... It's Aluminum,+ Not Pot Metal.....atleast by my Weight estimate,.... I wouldn't Really Know for Sure,....til I pull the trigger on the Welder

 

[Haut Medoc]

Re: What could account for these Exh Boot differences?

Well, I went & looked on mine & it is like the one you pictured & appear to be 4" dumps......
However the replacement risers I bought are definately 3" dumps.....
The Y pipe I bought has the 4" to 3" reducer 'boots'
The #'s match .....76351.....I'm officially baffled...:$.....JK
P.S. my risers are OEM....MC-20-60426 + 76351 are on the casting

 

[Boomyal]

Re: What could account for these Exh Boot differences?

Well, I went & looked on mine & it is like the one you pictured & appear to be 4" dumps......
However the replacement risers I bought are definately 3" dumps.....
The Y pipe I bought has the 4" to 3" reducer 'boots'
The #'s match .....76351.....I'm officially baffled...:$.....JK
P.S. my risers are OEM....MC-20-60426 + 76351 are on the casting

Sounds like I have created the mystery of the season. It's a good thing you got those boots with the Y tube. I think those belled boots are about $50 apiece. That was why I was thrilled to get a pair of boots for $32 shipped. Maybe that is why they were available because replacement risors all use the 3 to 4" belled boot and the straight boots just become surplus parts.

 

[Boomyal]

Re: What could account for these Exh Boot differences?

Ayuh,......
I just went out,+ Looked again,..... This 1 is also 3" outlets on the risers.....

I also measured the Intake, it's 9.1/4" between the bolts, C to C......

And,.. I pulled this Bracket we've been talking about,...
My 1st guess is,..... It's Aluminum,+ Not Pot Metal.....atleast by my Weight estimate,.... I wouldn't Really Know for Sure,....til I pull the trigger on the Welder

Bond-o, I'll try to develop some dimensional requirements for the bracket and get back to you. Then you can see if it worth an attempt to do anything. Two dimensions I could use from you is the distance between the cable fastening point on the carb bracket and the cable holder out at the back end of the bracket. Then the length of the current bracket from the front mount hole center back to the center of the cable holder.

I can then make a mock up to determine the proper cable bracket length for use with a 4 bbl.

Basically it would require two mods. One is the bracket length, the other would be the ctc width where the bracket would need to mount over the wider rear manifold/carb base studs for the 4 bbl application.

 

[Bondo]

Re: What could account for these Exh Boot differences?

This is getting Confusing,+ I think I started the Cross Topic talking.........

Anyways,......
I Think I've got the Exhaust Couplers you need,... They're noton the motor, but I Think I still have them with the Y-pipe,.... I'll have to Look tomorrow.....

 

[Boomyal]

Re: What could account for these Exh Boot differences?

This is getting Confusing,+ I think I started the Cross Topic talking.........

Anyways,......
I Think I've got the Exhaust Couplers you need,... They're noton the motor, but I Think I still have them with the Y-pipe,.... I'll have to Look tomorrow.....

Let me know Bond-o.

 

[Coors]

Re: What could account for these Exh Boot differences?

boom: that first pic, you have tiled garage floor, or forgiving wife, letting you put boat parts in house?

 

[Boomyal]

Re: What could account for these Exh Boot differences?

boom: that first pic, you have tiled garage floor, or forgiving wife, letting you put boat parts in house?

What she doesn't know won't hurt her, Coors. She was out that afternoon.8)