Author Topic: Manifolds and risers...again (Read 13338 times)

Rosscoe · « **on:** March 14, 2011, 06:16:18 PM »

I am finally ready to bite the bullet and buy some manifolds and risers and have pretty much decided on GLM's. I was going to get them through Moore Performance but due to lack of help from them, I've decided to take my business elsewhere. Claimed low profit margins etc for not being able to spend any time helping me figure out what I can use. Thank you very much.
I can very likely get the help I need here since there are quite a few that know this stuff as if its 2nd nature. Red comes to mind as well as Rich and Kip knows GM small blocks too. Others I am sure as well. I'll ltake any knowlege I can get.

I am probably going to take a bit of a chance when I do order but would like to be "reasonably" sure I can make them work.

SO with all that said....most of my poking around has yielded results for 83 and newer and I may have seen 81 and newer too but did GM change the heads around that time, that this should be a concern for me? If not, I am not sure why they are throwing that in there. Something must have changed?
I'll have to mess around getthing the plumbing hooked up since it will be quite different then stock but I'll worry about that more later. Same goes for hooking up the exhaust. That SHOULD just be a matter of getting longer hose to connect to the new center rise manifolds.

Rosscoe · « **Reply #1 on:** March 14, 2011, 06:18:48 PM »

I'm looking at CP Performance too which I found out is affiliated with Berkeley. Not sure which is the parent company but I dont see aluminum ones on their site. Moore sells both and I am really leaning towards aluminum.

GT150 JEFF · « **Reply #2 on:** March 14, 2011, 06:35:56 PM »

Ross

As far as I know a sbc head will fit any sbc block. The the heads changed I think in 1996 to a vortec head which is one one of the best free flowing heads to come out of GM. But with the vortec heads they take a different intake than pre 96. A vortec head bolt on will add close to 40hp with out touching the cam. So with a set of them a intake and a good cam right around 100hp added.

Hope this helps a little

Jeff

Rosscoe · « **Reply #3 on:** March 14, 2011, 06:41:10 PM »

Jeff if thats the only change then it seems to me any small block exhaust manifold should bolt right up.

So if I ever wanted to change to vortec heads, the old exhaust wouldnt work, is that correct?

OleRed · « **Reply #4 on:** March 14, 2011, 06:41:33 PM »

I can not imagine you not getting the help you nedded from Moore's performance, you obviously didn't get to talk to Dennis. Dennis has always answered any question I ever had, and I believe he has the best deals on the new stuff, I've bought several sets from him.

Refresh my memory, what are you working on ? the difference in the optoins are the exhaust system set-up, the heads didn't change, not for the manifolds to fit anyway, when you go from the old style manifolds, with the rear risers, to the later model center risers, you will need to change out the thermostat housing to go with the center rise set, and if you are going into a "y" pipe, a different set of elbows, often a reducer from 4" to a 3" "y" pipe.

CVX Fever · « **Reply #5 on:** March 14, 2011, 06:46:01 PM »

Ross,

Looks like a guy on ebay is selling a whole Hardin aluminum exhaust for your olds engine. Not sure if you want to deal w/used stuff or not. Per what Jeff said is there a reason you couldn't just use an exhaust system for an I/O on your jet. I can't off-hand think why it wouldn't work but there may be a reason.

http://cgi.ebay.com/ebaymotors/Oldsmobile-Hardin-350-400-455-Marine-Exhaust-Manifolds-_W0QQcmdZViewItemQQhashZitem20b7c74d1dQQitemZ140522245405QQptZVintageQ5fCarQ5fTruckQ5fPartsQ5fAccessories

Rosscoe · « **Reply #6 on:** March 14, 2011, 06:51:26 PM »

Its a 71 V175 with a 350 and jet.

I was a bit surprised at the lack of help He suggested some Cobra set up. I dunno
Kip I wouldnt mind used. I would like aluminum.

Rosscoe · « **Reply #7 on:** March 14, 2011, 06:53:54 PM »

This is the junk I took off.

GT150 JEFF · « **Reply #8 on:** March 14, 2011, 06:54:28 PM »

Ross

Yes the exhaust side is the same as any sbc. The intake side is what changed port heights and size.

Talked with Tanners marine parts guy few months ago and he stated that GLM exhaust manifold are some of the best stock looking manifold to buy.

Rosscoe · « **Reply #9 on:** March 14, 2011, 06:54:52 PM »

Here was the response from Moore
It was via email and was signed Dennis Moore

I am sorry about the lack of response on my part but I am asked how to make this conversion very often. I very seldom make a sale because I have no good answers.

I can sell you new "center riser" manifolds from a 1989 and newer OMC Cobra but they will not be an easy installation. The engines exhaust ports will be the same (there will be no problem bolting them to the engine) but connecting to the exhaust system will be difficult. Unfortunately I have yet to find an easy way to make the exhaust connection.

Because of the low profit margins selling on E-Bay I can not afford to spend much time with you on the problems of connecting them to your intermediate housing. Give it a try and let me know how it works out for you.

Rosscoe · « **Reply #10 on:** March 14, 2011, 06:56:50 PM »

Quote from: GT150 JEFF on March 14, 2011, 06:54:28 PM

Ross

Yes the exhaust side is the same as any sbc. The intake side is what changed port heights and size.

Talked with Tanners marine parts guy few months ago and he stated that GLM exhaust manifold are some of the best stock looking manifold to buy.

Yup that is where I heard about GLM but they didnt carry it and were offering me Sierra at close to 1900.00!

Rosscoe · « **Reply #11 on:** March 14, 2011, 06:58:33 PM »

Thermostat housing too? Where the heck do I get that? Stock wont work? Dang!

I agree that Moores prices are good and they come with stainless gaskets so it all seems good. That is why I stared there.
Now this thermostat housing stuff is bumming me.

Rosscoe · « **Reply #12 on:** March 14, 2011, 07:08:02 PM »

Quote from: CVX Fever on March 14, 2011, 06:46:01 PM

Ross,

Looks like a guy on ebay is selling a whole Hardin aluminum exhaust for your olds engine. Not sure if you want to deal w/used stuff or not. Per what Jeff said is there a reason you couldn't just use an exhaust system for an I/O on your jet. I can't off-hand think why it wouldn't work but there may be a reason.

http://cgi.ebay.com/ebaymotors/Oldsmobile-Hardin-350-400-455-Marine-Exhaust-Manifolds-_W0QQcmdZViewItemQQhashZitem20b7c74d1dQQitemZ140522245405QQptZVintageQ5fCarQ5fTruckQ5fPartsQ5fAccessories

I dont think there is any reason I can not use ones from an I/O as long as the angle of the risers are not pointing down too much to cause a kink in the hose.

GT150 JEFF · « **Reply #13 on:** March 14, 2011, 07:10:25 PM »

Looks to me as the is plenty of room.

What size are the existing thru hull fittings 3" or 4"

Grinder · « **Reply #14 on:** March 14, 2011, 07:29:19 PM »

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?

Rosscoe · « **Reply #15 on:** March 14, 2011, 07:40:15 PM »

3"
I think there should be plenty of room The old ones stuck out about 4" from the engine roughly and the merc cruisers are about that too.

I dont know what the deal is with the thermostat housing. Waiting to hear from Red again on that one.

Rosscoe · « **Reply #16 on:** March 14, 2011, 07:42:22 PM »

Quote from: Grinder on March 14, 2011, 07:29:19 PM

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?

Shaun
That sounds crappy. Funny, they talk about their process and how its suppose to be such a nice even casting. Where did you see bad stuff about them?

Grinder · « **Reply #17 on:** March 14, 2011, 07:55:58 PM »

Here is a couple of searches I did.

http://boards.trailerboats.com/cgi-bin/trailerboats/ubb/ultimatebb.cgi?ubb=get_topic;f=4;t=003280

http://www.google.com/search?hl=en&source=hp&q=glm+manifolds+reviews&aq=8v&aqi=g2g-v7g-b1&aql=&oq=GLM+manifold

Rosscoe · « **Reply #18 on:** March 14, 2011, 08:33:29 PM »

Its all giving me a headache. I just found an entire "kit" with thermostat housing and other stuff for 1300.00. Quite a jump from the 400.00 I am finding for just manifolds and risers. Argh!

Grinder · « **Reply #19 on:** March 14, 2011, 08:59:13 PM »

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.