GLM Performance Exhaust Manifolds

[jc]

I just finished repowering my 76 Spirit with new twin GM Performance crate engines Part #12486041. 350H.O. 330hp @ 5000rpm. Naturally I wanted to find a high performance exhaust to replace the old 3 inch riser/manifolds that I had without having to go with chrome headers or some of the other ridiculously priced "Marine performance exhaust systems".

After a pretty exhaustive search I finally stumbled across this website http://www.mooreperformance.org/index.html.

Appearently Mr. Dennis Moore is well known in the marine performance field although I hadn't heard of him myself. He has several books out on getting the most out of your Marine engines and is quite a nice guy to deal with. He makes Cast iron and Alum. Exhaust manifolds with an "internal header" built in for higher performance. http://www.mooreperformance.org/sitebuilder/images/DSCN3882-259x187.jpg

I purchased 2 sets of cast iron since my heads are cast and went with 4 inch risers.

I found his prices to be excellent compared to even stock Merc replacements and Mr. Moore threw in all the gaskets and new harware. I topped the motors with Bronze lined high rise aluminum Edelbrock performer RPM intakes, Holley 700 cfm marine carbs and Holley Hi-flo marine fuel pumps. I'm running Merc II transmissions and TRS outdrives.

The motors sound fantastic and are currently purring like kittens. I hope to have it in the water in the next few weeks and see just how much performance I have gained over the tired old 260hp Jaspers that were in it when I bought it.

Anyway I wanted to thank Dennis Moore for his assistance and thought I would point him out to fellow Donzi owners that may be considering manifolds or other marine related parts in the future. Thanx --jc--

[MOP]

Quite a few of the members have bought his setups, I am thinking of a set for myself. I am leaning toward the iron also as from the cut aways the Iron has better out tubes without the square corners of the aluminum one. The cut away you show is the aluminum one "below is the iron one". The iron is heavier but I think performance will be a little better.

MOP

[Walt. H.]

I to just placed an order this past monday from "Dennis Moore" for a set of "aluminum" exh manifolds for my small block and I will be topping them off with a set of Imco s/s perf, riser's :) that I was originally planning to put on my 1/2 season old stock black Merc manifolds. Besides the weight loss and the improved flow they'll also look great once I polish them out to at least a orange peel texture. :yes:

Up date note worth mentioning:
If I didn't already have those riser's I would have gone with the complete package using everything from Dennis Moore!!


Keeping it fun, :checkered

Walt

Ps, Have you seen the new "marine payphones" floating around your local bay area?

LMAO, again!!

[Dennis Moore]

Thanks for the kind words.

We changed the tooling a little from the cutaway photo on my web site. The center exhaust port dividers have a little curve in the new manifolds. Don't know if it will help any but we are always refining the design for maximum performance. Since we simply have to change a styrofoam core, the changes can be made easily.

The neat part about the "lost foam casting process" is that the same tooling can be used for aluminum and cast iron. We are looking into the cost of producing the manifolds out of pure stainless steel as well as aluminum and cast iron. Stainless steel ingots are very expensive and the manifolds will be heavy. The cost to manufacture and ship will be considerably higher than with cast iron or aluminum. We will have a 7 year warranty on them if we can make it happen at a (somewhat) reasonable price.

Sincerely
Dennis Moore

[raritan]

What is the lead time on these manifolds.

[harbormaster]

Sweet!

Thanks for the Post Dennis

[Walt. H.]

Well guy's I ordered a set of Aluminum exh manifolds on Monday morning this past week and they just arrived a half hour ago today.(Sat) 5-days from Cal. to NY, via Fed Ex, You can't beat that for fast regular mailing. :checkered

O' yeah they are better than I expected in fact they look just great inside & out and 1/3rd the weight of iron yippie :checkered . I ordered them unfinished expecting to grind and polish but I think they look just find as is, just like an Edelbrock intake manifold right out of the box new.

And WOW! a'm I impressed with those individual runners!

Thanks Dennis, :wavey:

Walt

[MOP]

So who is buying the donuts early or beer late, don't you dare put those suckers on until I take a peek!

Mean Old Phil! :biggrin.:

[Walt. H.]

Phil,

We'll figure out a day for you to look see and fondle them to your heart's content, :smileybo: because I don't think my old lady would like you peeking under our cover's. :embarasse

Ps, they don't weigh any more then a 12-pack of bottled beer each without the riser's. :yippie: :checkered

Still keeping it fun, :beer: :party:

Walt

[Rootsy]

poodle,

i ordered a pair of these mainly for weight savings and i asked this question directly to dennis... and all i could get out of him was you should maybe see a 1 to 2 mph gain :bonk: not quite what i was looking for ya know... cause that isn't a very quantitative answer... 1 mph for me isn't equal to 1 mph for some guy running a 38 zr...

JR - unwraveler of secrets ;)

[Walt. H.]

Hey Hi there Poodle,


This is only my view and not the gospel!

I would say its more of a percentage improvement because saving 60 - 64 lbs, will have more of an improvement gain in a 2200 lbs, boat then lets say in a 4200 lbs, boat, and its the same with race cars when gutting weight.
But as far as will the "GLM exh manifolds" flow better and improve H/P over the stock open box manifolds? I believe so!
Here's the reason: Boy ! i'm going to catch hell with this scenario. :idea: Exh, gasses are like little children leaving the "class room or the cyl, head" then finding themselves in the "school hall or the exh, manifold". They need guildence and direction to find the shortest way to get from one class room to the next on time or the exh outlet. If they're not shown the way, they're loiter bunch up and some will go in the wrong direction causing a delay. :confused: Are you guy's laughing yet? :yes: The improvement again can only be measured in percentages, based on how much H/P the engine is producing or trying to produce. Either way its a win,win situation over not chosing the stock open box design and chosing the one's with the internal runner's.

What surprises me more is that most people will accept and not question or challege some of the increase h/p claims aftermarket air breather/filter manufactures make to the public if you just install their pretty unit's on top of your carburator, throttle body or the fuel injector air box assembly. They are hopeing your OEM was dirty and glogged for you to feel the gain. But usually never give much thought to whats inside of their own exh, system.

Again, This is only my view and not the gospel!

If your engine is stock to mildly modified I think the GLM exh set up is the best "Bang for the Buck" you could ever make. Everything else is just status and looks unless you have a radical fire breathing monster then by all means spend for the $1500.00 to the multi thousand dollar jobs.


Keeping it fun & wet,

Walt

[smoothie]

Hey Walt...you know the guy that bought the manifolds and air cleaner...now he went ahead and bought the pulleys :jestera: All BS aside the I think the Dennis manifolds are a good buy if you need a new set or for the weight.PS the added 1 to 2 mph is only valid in the spring and the fall!

signed LOGHEAD

[Sam]

Walt, I love the kids twist. For once I understand what you gear heads are talking about. You should consider writing a book.

Sam :cool:

[Rootsy]

WHAT? you don;t understand me Sam? guess i'll have to start using baby talk... sheesh

JR

[MOP]

Walt, I love the kids twist. For once I understand what you gear heads are talking about. You should consider writing a book.

Sam :cool:

Oh God don't ask him to do that! He is hard enough to put up with now :biggrin: :biggrin: :outtahere

[Walt. H.]

Yeah! i'll call it "Mikey the Manifold" and Uncle Phil can narrate, Ha ha! :jestera: :umbrella: :biggrin: :checkered


Thanks, :rolleyes:

Walt

[olredalert]

-------All this talk got me to call Dennis this morning and put in my order for a pair of un-powdercoated manifolds for the new Scorpion. They will go nicely with the Rex stainless risers I installed last season. If you think the price is good for the black ones just ask him for the price of an un-powdercoated pair. Very reasonable and seemed nice to deal with!.............Bill S

[jc]

-------All this talk got me to call Dennis this morning and put in my order for a pair of un-powdercoated manifolds for the new Scorpion. They will go nicely with the Rex stainless risers I installed last season. If you think the price is good for the black ones just ask him for the price of an un-powdercoated pair. Very reasonable and seemed nice to deal with!.............Bill S

:beer: I think you'll be pleased. Glad I posted about Dennis. I hope that got you looking, of course his prices and pleasant attitude sold you.

[bigman]

New alum manifolds arived today. They look real good. I'm going to have them powdercoated in gold, black bolts hope they turn out good. Hope I notice the loss of wieght.