Manifolds and risers...again

[OleRed]

Ross,

I would do some research on the GLM's. I was looking at them before I bought my merc manifolds. The info I found was more often then not they are not machined very well on the mateing surfaces which causes leaks internal and external. I don't have any experiance with them but this is what I found. What is the difference with the Thermostat housing?

I've seen those negitive reviews about the GLM manifolds,  from three years ago, and the one fellow that chimed in bought a used set off ebay, installed them some time later and ran them two years before he had a problem, I don't know about any of that, all I know is I have bought three sets from Dennis Moore, two aluminum sets, one cast iron set, and the only issue I had with them, may not have been necessary, but I ran a tap through all the threaded ports to get the nipples to twist further into the ports, looks better to me.  The brand new Thunder exhaust I recently bought will get the same treatment, the threads just don't seem to be dressed enough to to allow the nipples to screw into the ports far enough.

[OleRed]

Rosscoe, I didn't realize you were working on a jet system, I've only delt with a couple of those, 455 Olds, and a 460 Ford, but I believe the manifolds you removed are old school OMC, good plan to get rid of those, in my opinion.  I think there may be an issue about the difference in the supply pressure from a jet bowl, rather than the I/0. I kinda stick with the Mercruiser stuff and I'm probably not help when it comes to the jets.

[wiliermdb]

http://boatstoreonline.com/glmexhaust.html

Anyone ever used Glenwood Marine Magnaflow manifolds?  A friend of mine was looking at this and mentioned that his dad had ordered a set of Glenwood's for his boat a year or two ago.

[Grinder]

Red,

What's the difference in the thermostat housing? Will the older style work?

[OleRed]

The older style Mercruiser manifolds (log style, with the rear risers, require three cooling ports on each side from the thermostat housing, the later certer rise manifolds only require 2 on each, and there are spring tensioned restrictor balls in the thermostat housings for the center rise manifolds from the late 80's and 90's.

[Grinder]

Could you just plug 2 of the ports, or do I have to buy a new housing? What do the restrictor balls do?

[Rosscoe]

Rosscoe, I didn't realize you were working on a jet system, I've only delt with a couple of those, 455 Olds, and a 460 Ford, but I believe the manifolds you removed are old school OMC, good plan to get rid of those, in my opinion.  I think there may be an issue about the difference in the supply pressure from a jet bowl, rather than the I/0. I kinda stick with the Mercruiser stuff and I'm probably not help when it comes to the jets.

Glad to know you  have personal experience with them. Like you said Dennis Moore has the best prices. I'm going to call and order some soon. I havent made up my mind on aluminum or iron yet.
So Red what were you talking about when you mentioned the thermostat housing? Why would I need to change that? I have no idea.

[Rosscoe]

I'm not saying don't buy them, just make sure to check with people who have used them (I have not used them). What I have read, alot of the people say buy mercury manifolds for the fact of not having problems later. The reason I bought the mercury manifolds was they are only 3 years old, they are the dry joint (1 less gasket to leak), and they were a little less than an aftermarket kit. I was also reading that one guy said to buy OSCO manifolds but I don't know? I had the same headache last week for 2-3 days till I just hit the BUY IT NOW button then my headache went away.  

LOL
Dry joint? SO you bought some used mercruisers?

[Grinder]

Ya I bought a set off of a '07 or '08 boat that they changed out to performance exhaust.

[Rosscoe]

Those look pretty mint.
Yeah I was thinking the same thing. Why couldnt I plug the extras, but I did look at it tonight and I saw one large hose from/to the water pump and two going to each manifold. The risers were "jumpered together in the rear so I just dont know what that is all about. Guess I'll be winging some of this for sure. First thing is to get it running. Wish I could do that here but I know of no good way to make sure the impeller and engine are getting water. I'd have to lower the rear end into a large tank!
I never even thought about pressure issues but its all the same water so I just dont know.
Not sure how a guy would trouble shoot that either.
Live and learn. I dont think I'll buy something like this again. Thought it all would be a bit easier.

[CVX Fever]

Looks like a guy on ebay is selling a whole Hardin aluminum exhaust for your olds engine

Ross I'm not sure how I got it in my head that your boat had an Olds engine but I was under the hood of my Cutlass enough to know that after looking at the picture you posted on this thread, you don't. Looks like a SBC to me which is good news as that opens up your options for exhaust.

I would think that if you go w/a MerCruiser center rise manifold,  you could get the thermostat adapter and then plumb it like Jeff's boat. Hopefully there wouldn't be too much more to it than that. 

[Rosscoe]

Dont sweat it. Maybe the color? Actually a 65 Buick I had, the engine was green. My 442 was gold but someone had been in that motor big time and could have painted it.
I'm glad you brought it up. Had I bought chev stuff and found out I had an Olds, I would have been ticked,  but with the question being raised and Jeff doing some digging for me, I was able to confirm it is a chev. I found new ways to differentiate because if it too. The easiest one was the distributor. Since it goes thru the intake its a chev. Had the intake been cut away back there, then Olds. 
The other surprise to me is that 350 and 455 olds are dang near the same. 

I was just happy to find out it was a chev. Parts are so much more available and cheaper!
I still havent ordered yet. Cant make up my mind about the aluminum and if I'm going to order from Moore Perfomance or not. That is the only place I have found GLM aluminum ones. Otherwise cast. I am trying to think ahead and was even considering going with 4" exhaust and reducing it for the time being with the thought of doing more to the engine in the future, OR save money now just in case the motor is trashed. I dont know. Guess I could always sell the cast iron 3" at a later date too. About a 200.00 difference.

[Rosscoe]

Anyone know what the deal is with these?

 2 STAINLESS STEEL MERCRUISER EXHAUST GASKETS RESTRICTEDSTAINLESS STEEL RISER ELBOW GASKET 1983-03 V6 V8
   
 2 STAINLESS STEEL MERCRUISER EXHAUST GASKETS BLOCKED STAINLESS STEEL RISER ELBOW GASKET 1983-03 V6 V8