4.3 and 5.7 y pipe... are they the same size?

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
Re: 4.3 and 5.7 y pipe... are they the same size?

yes...
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
Re: 4.3 and 5.7 y pipe... are they the same size?

Welcome.
 

45Auto

Commander
Joined
May 31, 2002
Messages
2,842
Re: 4.3 and 5.7 y pipe... are they the same size?

Check the hole locations where it joins to the sternplate. You need to know what you have. Some have 4 holes in an equally spaced pattern, some have 4 holes in an offset pattern. My '87 Searay with twin 350's and Alpha outdrives had one of each from the factory .....

3 of the holes are in the same location, the 4th one won't line up if it's the wrong Y-tube and you'll have to hope some silicon will keep it from leaking on you. You'll be MUCH better off getting the correct one unless you want to pull the engine again later to stop the leak ....

Y-pipe with symmetrical mounting holes:



Sternplate with offset mounting hole:

 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
Re: 4.3 and 5.7 y pipe... are they the same size?

Quick correct... As the OP had used engine capacity (in litres not cu in) I assumed he was talking late model. The pipes for those have the same part number...

Chris..........
 

krisnowicki

Lieutenant Junior Grade
Joined
Jul 11, 2007
Messages
1,172
Re: 4.3 and 5.7 y pipe... are they the same size?

I am not changing the y pipe just the engine so we will be good.
 

smokeonthewater

Fleet Admiral
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Dec 3, 2009
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9,838
Re: 4.3 and 5.7 y pipe... are they the same size?

Maybe we should make SURE we are talking about mercruiser here
 

45Auto

Commander
Joined
May 31, 2002
Messages
2,842
Re: 4.3 and 5.7 y pipe... are they the same size?

Maybe we should make SURE we are talking about mercruiser here

Seemed like a good bet to me, based on the original posters signature .....

From Post #1 Sig:

"Prudence Prevails"
1992 221 Four Winns Liberator
Merc Alpha One Gen 1
Merc Mag 350
 

smokeonthewater

Fleet Admiral
Joined
Dec 3, 2009
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9,838
Re: 4.3 and 5.7 y pipe... are they the same size?

well I saw that but didn't figure he was pulling a 5.7 for a 4.3...... just figured it was worth double checking... might save him some coin
 

krisnowicki

Lieutenant Junior Grade
Joined
Jul 11, 2007
Messages
1,172
Re: 4.3 and 5.7 y pipe... are they the same size?

I found a deal on a 23 maxum with a 4.3 in it. I am going to swap t for a 5.0 or 5.7. The liberator is going on the market.
 

smokeonthewater

Fleet Admiral
Joined
Dec 3, 2009
Messages
9,838
Re: 4.3 and 5.7 y pipe... are they the same size?

so is it a mercruiser? what year is it?..... measure to make sure you have room for the longer engine and also look at the engine mounts.... the v8 will mount at a different place than the v6.... If it simply bolts to the top of the stringers there should be no prob there but some hulls have formed mounting pads located for the engine installed....... all else being equal I'd consider just swapping the engines between the two boats and selling your boat with the 4.3 in it
 
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