Conversion from Rear to Center Manifolds

[haulnazz15]

Does anyone have any experience with swapping the log style aft exit exhaust manifolds to a center-exit manifold? My manifolds/risers are who knows how old (over 15 years for sure, quite likely original equipment (33 years). In any case, I believe that the failure of the riser or manifold is what has caused the water in my 351W. I have secured the purchase of a 90's 351W long block to swap in, but I don't want to reuse the manifolds that likely caused the problem in the first place.

I have seen many of the center-riser manifolds that look like they were used in the inboards, possible some of the inboard/outboard applications. Is it possible to convert to the center-riser and still use the y-pipe design instead of making it a thru-hull? It seems like you'd only need to buy the risers and manifolds then find a length of rubber exhaust tube to connect the riser/y-tube.

 

[Bondo]

Re: Conversion from Rear to Center Manifolds

It seems like you'd only need to buy the risers and manifolds then find a length of rubber exhaust tube to connect the riser/y-tube.

Ayuh,... There's usually also a cast down-turning pipe in there as well....

The Issue you might have is,...
Manifolds for a Ford motor are Rare to Non-existent...

 

[haulnazz15]

Re: Conversion from Rear to Center Manifolds

Actually there are plenty of them around. Even here on iboats, but again, they are center-riser manifolds, not the aft-risers. I can find the aft-risers on two sites, not including ebay which seems to have a number of different vendors for them. Availability is not the issue. The Mastercrafts and Ski Nautics, etc, used the 5.8L in there early to mid-90's boats which all use the center riser. My question was simply if it was possible to use those enter-riser manifolds even though the y-tube wasn't deisgned with them. If all that is involved is a piece of 3" curved pipe and some rubber couplers I would do it.

 

[Haut Medoc]

Re: Conversion from Rear to Center Manifolds

You can get log type manifolds & risers all day long & bolt them right on....
Or, you can get the center ones & get the elbows & exhaust hoses & go that route......
A warning: If you go with center rise, you will need to figure out a way to bolt the water separator & the slave solenoid on.....

 

[haulnazz15]

Re: Conversion from Rear to Center Manifolds

You can get log type manifolds & risers all day long & bolt them right on....
Or, you can get the center ones & get the elbows & exhaust hoses & go that route......
A warning: If you go with center rise, you will need to figure out a way to bolt the water separator & the slave solenoid on.....

You know I did think about that, I wonder where the mastercrafts mount the water separators? It may not even be worth my time to do the conversion, but the log style are almost 2X's the price of the center risers in some cases. The slave solenoid could be mounted to just about anything though as long as it is still connected to the starter.