exhaust manifold/riser layout question
 

Hey guys, I have a question, I am trying to make my engine rebuild as speedy as possible and I know these days that's a hard task. So my 502 is at the machine shop it suffered a bag head gasket last season and I trying to plan how aggressive I can get with the rebuild without breaking the budget or creating something that will not be enjoyable and become more of a hassle.

The boat is a 1996 Baja 252, its a cookie cutter boat and I currently have EMI Thunder manifolds and cast risers, I want to replace the cast risers with SS mandrel bent risers and potentially delete the silent choice along with the Y-pipe. I spoke with Eddie Marine and they are telling me before I can order them I need to do a custom mock up with PVC pipe. SO I have NO motor in the boat and it is shrink wrapped for winter so now I cant order. My Transom and exhaust is STOCK and not modified, why would they not have a replacement. If I were to rebuy the entire kit your telling me I would have to do a mock up before hand??????
I'm trying to gather all my parts so as soon as spring arrives and the motor is back I can start assembling to be ready for May. Only positive thing he did say is they can add O2 sensor bungs because Im running Holley HP injection on the boat.

Sorry for the rant but does this make sense? If it does then I will be getting a plastic mock up block from Jegs and wasting $500 so I can get their measurements ASAP.

"cookie cutter" boats are not built on a modern assembly line by robots. They are all a little different and I can't blame any vendor for wanting to be sure you're ordering correctly the first time.

What are we missing here ?

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I never looked at the complete system as the boat already had them when I bought it and was just looking at risers. Sure poses an issue being their is no motor in the boat at the moment to measure off of. My question is if the cast riser on their system lines up perfectly why would the stainless riser be different? Now do I run the risk it doesn't line up or do I buy a plastic block to get in the boat for mockup for $500 to save me time?

If your existing exhaust tips are in the factory Bravo locations, the long risers should line right up. The taller HP500 risers should as well since they drop down to the same exit location. You have the manifolds already, it really is as simple as just buying your desired stainless risers from EMI. I would opt to get a oxygen sensor bung welded into each one also.

I was not suggesting the full system.
I wouldn’t think your manifold is any different than that one.

I’m with you. What are we missing ? The literature shown says what we think.

Was there a communication issue between you and the phone person ?
Are your tailpipes in non Bravo position ?

I was pretty clear its a 1996 Baja 252 with a original untouched transom, Bravo 1 with a mercruiser 502 Mag MPI. I said if I already have you exhaust system on my boat with cast risers what is the confusion about swapping over to the SS pipe risers? It currently has the factory Silent choice Y-tee's as well. I think this is called CYA (cover your ass) in the chance it doesn't line up they want me to understand its MY PROBLEM! $1,500 to $1,900.00 depending on what I choose.

I bought 2 sets of those risers last year. Have not had a chance to install them. I don't recall them asking me to do anything to see if they fit. They sell the taller stainless riser too that I can see might be a problem. Now that I've seen your post, I have one more thing to worry about. I did have them install the 02 bungs however they only installed in one of the risers per engine so if you need both done, you will have to let them know. Good luck.

One would think if it's offered for a Bravo set up, it'd naturally fit a boat set up new with a Bravo. If by chance there's a small variance alter the holes and make a plate to cover if needed. Just like I had to do when I raised my out drive 2". Really, it's not rocket science.
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I bought the entire system (2 systems) a few years ago so I have both the old and new risers from Eddie Marine. I have not installed the new stainless risers on my boat yet and after giving it some thought, I do remember making up a template to see if they would work. The more rubber exhaust hose you have after the riser the more it could be off alignment and still work. They show a little higher than the stock but only 1-1/2" or so. It has been almost 2 years ago that I ordered them (It didn't take 2 years to get them) and I assume after I made the template I was pretty sure they would work on my boat. At least I hope that will be the case. Let me know if you need more info.
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I too find it a bit odd that they are talking about a mock up...frankly haven't heard of that when it comes to a supplier simply providing a system that is a replacement for a Mercruiser factory unit. Baja was a great builder in those Bucyrus days, good craftsmanship. They built 152 of your model boats that year, so I imagine they had a reliable, repeatable process for installing exhaust systems. As PQ290Enticer noted, you should have some 'wiggle room' with the rubber hose part of the system, won't you?

So I called Eddie Marine again yesterday and spoke to a different person, seemed to be a bit more knowledgeable on this situation. I told him I have a 96 Baja 252 with an untouched transom but my current 502 is equipped with a Eddie Marine thunder manifold & cast riser setup. I simply want to switch out the cast risers for the SS risers and eliminate the T/Y for the silent choice and have the riser meet directly to the exhaust tip which I believe is also an Eddie Marine replacement.

I then told him I had spoken to a team member of his previously but I was confused as to why I would need to perform a mock up when this is a Bravo 1 factory original setup. He told me the replacement SS risers "should" line right up and yes they can weld in the O2 bungs and I am looking at about a 2 week turn around but for the mock up he would prefer I do it and take measurements for confirmation of fitment. So basically they believe it will fit but if it doesn't, don't call them back to ***** because you have been WARNED. Typical CYA scenario.

I'm on the fence on wither to wait until the engine is back from the machine shop or to just hope for the best. I think I can take the measurements with the engine on a stand and not in the boat but I'm a long way from getting it in the boat and it seems like summer is a long way out but in reality it really isn't at all!

I'm doing this for 2 reasons:
A. I want to bump up the cam profile slightly
B. I'm eliminating the silent choice and installing complete Holley HP multi-port injection system to eliminate the stone age MPI system it currently has with a MEFI 1 ECU.

PQ290Enticer: judging by your photos it looks like a direct replacement, where you have the rubber tube I have the silent choice TEE so I do not have any rubber tube just 4 couplers which makes me believe as long as the overall length is correct the angle from riser to tip should be fine. If it comes up short I can lengthen it with a pice of that rubber hose, it its too short I assume I can cut it in a band saw? Angle is the elephant in the room here!