Mercruiser 7.4L Manifolds & Risers

[Mr Mac]

We are looking to replace the manifolds and risers in our Sea Ray 330 with its twin 7.4L Mercruiser engines and I am looking at all options as far as manufacturers and their warranties. I had one person tell me to stick with OEM parts with their one year warranty and others tell me that aftermarket parts (i.e. Barr, OSCO, etc.) with their 3 year warranties are just fine.

What I need is actual thoughts from folks who may have moved from OEM to one of the aftermarket manufacturers and if you're happy with the decision or not.

[Chuck34]

Quick question...is you engine RWC or a full FWC? If a full FWC, more than likely there is no need to replace manifolds. Risers, yes.

[Mr Mac]

It is RWC system and our boating area is the Gulf of Mexico and our slip is also salt water.

[two-rocks]

On my old boat, I didn’t like the 454 manifolds (during an engine build from scratch) and went with the mercruiser 496 setup. It used a dry joint and is much better because of that. I went a step further and did a custom a full FWC setup. The 496 risers are SS and will last a very long time. The 496 manifolds and risers will work on a 454.

In your case, use any brand - you need to pitch the whole system (manifolds and risers ) at 5 years Max. They are cheap compared to a new engine. Salt water is not the friend of the poorly designed mercury 454 exhaust.

[David M]

Consider stainless steel risers. They will never rust out again as the cast iron ones do so frequently in salt water.

[Taipe]

HDI Marine of Vancouver, WA makes after market manifolds & risers out of 316SS. I have used them and can vouch for the excellent quality. Contact them and see if they have what you need.

[Squanderbucks]

If you choose to stay close to the original setup and not start doing custom stuff the I would recommend either OEM or a quality name brand company like Barr. There is no comparison to the metal castings they make and the generic (read Chinese or Indian) stuff that is out there on the internet at somewhat lower prices. shipping the same, installation labor costs the same but they rust out in no time.

[Mr Mac]

Originally Posted by Squanderbucks

If you choose to stay close to the original setup and not start doing custom stuff the I would recommend either OEM or a quality name brand company like Barr. There is no comparison to the metal castings they make and the generic (read Chinese or Indian) stuff that is out there on the internet at somewhat lower prices. shipping the same, installation labor costs the same but they rust out in no time.

I was never contemplating anything from overseas! Too many manufacturing variances when compared to the stuff made here which is why I only called out the three. I think I will end up with the Mercruiser or Barr stuff just because when it comes to marine engine parts, where it's made is every bit as important to by who. Barr (last I heard) has a 3 year warranty versus Mercruiser's one, so they will likely get the nod in this case.