Exhaust suggestions 7.4 MPI

[lildogcustoms]

Current setup is 7.4 MPI- I have been looking at Stainless Marine and Revolution Marine- Not set on either but like pricing-Suggestions???

[harbormaster]

I am a big fan of the stainless marine ones...

[VetteLT193]

one of the benefits of stainless marine is the round mount on the riser. The round mount gives you some side to side freedom to get the holes lined up in the transom.

Most of the aftermarket systems use the 4 bolt system on the riser, and with long riser and 'hard' 4 bolt mount, if it doesn't line up then too bad... break out a saw or a welder.

However, even with that said, I just bought EMI Thunder. Very nice quality stuff. I haven't installed it yet, waiting on the boat to get back to me. I have my fingers crossed that everything lines up. :crossfing:

[VetteLT193]

Also, depending on your boat, my brother has a set of used GIL offshore for sale, set up for a 22 Classic. They were custom welded by the guy from Popeye's racing so you don't have to put holes in the transom for the water dumps. I know he'll let them go pretty cheap. The down side is they are LOUD.

[BigGrizzly]

For that engine I prefer the Stainless Marine, in real duno test the rival the tube hedders. They fit well look good and silent choice can be added easily. Ecm tuning is not necessary. A side note Stainless makes a lot fittings and stuff for the other companies.

[lildogcustoms]

Boat is 26zx- What about Dana Marine Exhaust?

[zelatore]

Timely post....I'm also looking for a set of manifolds for my 502 to install over the winter.

Who's the best vendor for Stainless Marine stuff? Looks like they don't sell direct. Anybody on the board? It's alwasy nice to support the family.

[CJmike]

http://www.donzi.net/forums/showthread.php?t=52994

[VetteLT193]

Timely post....I'm also looking for a set of manifolds for my 502 to install over the winter.
Who's the best vendor for Stainless Marine stuff? Looks like they don't sell direct. Anybody on the board? It's alwasy nice to support the family.

I'm pretty sure madpoodle deals in SM.

[zelatore]

Ahhh...I knew somebody on here was a disty, but I keep getting all those Florida boys confused.

I think there's really only one Florida guy. Poodle, Buzzilla, Griz....they're all the same person, right?

[gcarter]

Ahhh...I knew somebody on here was a disty, but I keep getting all those Florida boys confused.
I think there's really only one Florida guy. Poodle, Buzzilla, Griz....they're all the same person, right?
Poodle and Buiz definately are joined at the hip...I've seen them both at the same time, so one person using a disguise is out.....But they could be fraternal twins.
Catch22 and Cuda are also joined at the hip.:propeller:

I know for a fact Griz lives in Georgia.

I don't get along with anybody.:wink:

[zelatore]

http://www.donzi.net/forums/showthread.php?t=52994

Yup. Saw those but so far I'm thinking I want to keep my quick and quiet (even though I almost never use it).

Still, they are shiny. :)

[SilverBack]

I have heard very good stuff about the Stainless Marine stuff. I went with the IMCO Powerflow on my blown 502 and that was one thing that worked great right out of the box and looks great and was not really crazy high on the price. I have seen several sets on ebay that were brand new for just a few hundred on ebay after I bought my set.

[kd5cue]

I have heard very good stuff about the Stainless Marine stuff. I went with the IMCO Powerflow on my blown 502 and that was one thing that worked great right out of the box and looks great and was not really crazy high on the price. I have seen several sets on ebay that were brand new for just a few hundred on ebay after I bought my set.did see any hp gain?

[SilverBack]

It is hard to say exactly what was gained...I went from a bone stock 502 MAG to a full race aluminum head blown 502 with 750 HP after it was tuned back down. I had these manifolds and the engine was making 890 hp. I changed cams, supercharger pulleys, injectors and computers to back it back down to the 725 - 750 HP range.

I am sure that they would have made a diffence if all I did was change from stock to the IMCO exhaust though.

[lildogcustoms]

Anyone know anything about Kodiak Marine???

[The Hedgehog]

It is hard to say exactly what was gained...I went from a bone stock 502 MAG to a full race aluminum head blown 502 with 750 HP after it was tuned back down. I had these manifolds and the engine was making 890 hp. I changed cams, supercharger pulleys, injectors and computers to back it back down to the 725 - 750 HP range.

I am sure that they would have made a diffence if all I did was change from stock to the IMCO exhaust though.

Did they use these manifolds on the dyno pull? 890 hp is a lot of hp for power flows and most dynos use headers.

[The Hedgehog]

Those Dana's I am selling have both the bling and bang for the buck.

They have 27 inch runners that extend into the SS risers. KE makes a set with the long runners but they look like a cinnamon roll cut in half.

[VetteLT193]

Anyone know anything about Kodiak Marine???

If they are the ones I'm thinking of they are similar the GLM aluminum? If you don't care about getting a long stainless riser with the water dumps down the line (i.e. big cam exhaust) GLM is the budget choice. I just did a bunch of searching and found GLM aluminum with risers for 600-700 shipped on eBay for the pair. (keep in mind I am shopping for a small block).

-Eddie Marine are a bit over $1k for the standard style riser.
-The true EMI Thunder with the long stainless riser are in the $1800 area.
-Stainless marine seemed to be about the same as Eddie but the riser isn't as long... I call SM risers 'mid length'. better than stock but not full length.
-I also cross checked Gil, they only make Big Block exhaust that I know of, and were in the mid $2k range.
-CMI are regarded as the 'best' but are $$$$

-I checked others and am happy to share if you have any other comparables. I think I looked at them all at one point or another.

In my opinion, you can buy used for the best deal. I bought my EMI Thunder used (4 hours of run time, big deal) and saved a ton.

[BigGrizzly]

I noticed that you want to use the quick and quiet- same as silent choice. Stainless is a bolt on system. To me they look great, put them on many boats and never had a complaint. They were on my son's wipple charged 7.4 22ZX worked great. They are not on my Criterion because we built the engine around the tube hedders, if it weren't for that they would be on it. as for Dana there isn't enough information on them except for a few bias opinions and a couple of good Donzi board members who like them. We haven't dynoed these yet in a real comparison, so I can't give you that answer.

[SilverBack]

Did they use these manifolds on the dyno pull? 890 hp is a lot of hp for power flows and most dynos use headers.

DWM used my manifolds but his risers. I know that because I did not have my risers when he did the pulls that he did. Mark at precision said that he was using my manifolds but I don't know about risers. I know this because I was talking to him on the phone and he walked outside with the phone and let me hear my exhaust while the engine was running. The engine was only making 700 HP at that time though and never made better than 729 on his dyno so who knows. I am pretty sure that he was using my risers though. I think he may use headers when he first starts out to see if a cylinder is leaning out or whatever but then he goes to the risers if that is what you are running.

I know that Eddie puts those dyno headers on when he dynos but then when you go to the real setup things change and I know that David and I think Mark think that you are better to dyno with what you are really going to run.

I think that I read that IMCO rates those manifolds for for 1000 HP and 575 CI displacement. The powerflow plus are rated to 1300 HP.

David says that he would put them up against the CMI headers on my application.

[BUIZILLA]

IMO, I wouldn't waste big money on a high dollar setup for a basic 310 peanut port truck engine...

[BigGrizzly]

For your application Buiz would be correct don't spend too much unless there is a change coming in the near future.

[lildogcustoms]

I'm going to upgrade in the future- Just don't know what "future" timeline is...Will be looking at 500 EFI or 525 just depends on budget at that time but I'm wanting to pick up some basics now and then to less'N the blow when it comes time to pull the trigger....you know picking little things up along the way keeping them of the wife's radar!!!!!! :wink::wink::wink:

[VetteLT193]

I'm going to upgrade in the future- Just don't know what "future" timeline is...Will be looking at 500 EFI or 525 just depends on budget at that time but I'm wanting to pick up some basics now and then to less'N the blow when it comes time to pull the trigger....you know picking little things up along the way keeping them of the wife's radar!!!!!! :wink::wink::wink:

In my opinion it comes down to Dollars and sense. If your master plan is to have a 500 or 525 in the boat you are going to want an exhaust set up with dumps way down, or dry exhaust.

that means you are at EMI with the stainless risers at the low end... CMI's would be my choice for either 500/525 but is a couple hundred RPM's worth the extra $2k? that is a decision for you to make.

[The Hedgehog]

DWM used my manifolds but his risers. I know that because I did not have my risers when he did the pulls that he did. Mark at precision said that he was using my manifolds but I don't know about risers. I know this because I was talking to him on the phone and he walked outside with the phone and let me hear my exhaust while the engine was running. The engine was only making 700 HP at that time though and never made better than 729 on his dyno so who knows. I am pretty sure that he was using my risers though. I think he may use headers when he first starts out to see if a cylinder is leaning out or whatever but then he goes to the risers if that is what you are running.

I know that Eddie puts those dyno headers on when he dynos but then when you go to the real setup things change and I know that David and I think Mark think that you are better to dyno with what you are really going to run.

I think that I read that IMCO rates those manifolds for for 1000 HP and 575 CI displacement. The powerflow plus are rated to 1300 HP.

David says that he would put them up against the CMI headers on my application.

Eddie compensates for the difference on the dyno and then tunes it in the boat. You can't get more real life than that. One thing to consider on the dyno header issue is that with dry headers you can monitor EGTs on a cylinder level. That becomes more important when using bigger intakes and batch fire injectors. That becomes even more important when trying to detune and engine that wants to make big power.

I know that Mark is a fan on tuning again in the boat too.

I would probably say that most engine builders use dry headers on the dyno. Wet exhaust on the dyno is good, you just need to have them set up right. I know that Mark Boos and Tyler Crocket use them.

[BigGrizzly]

A lot of us use the boat hedders for final tuning on the dyno. We start with dry hedders because of the plumming until we get it dynoed then final with the boat hedders. the problem with boat hedders you need a probe in each exhaust port. and most don't make a provision for them. Mark is correct in my opinion that boat tuning is the best way to go on the final step. His problem is his location it is usually at a low sea level and very humid, this doesn't help in Michigan. As for the Imco vs EMI vs CMI and the final ratings, CMI has several versiona from step tube to big tube. How many race boats use CMI and Stelling compaired to the others, almost all of them.
The Merc HP500, 575 etc all use CMI. No there is also a big performance hedder from Stainless Marine, Harding Keith Eckert, and the list goes on. So pick your poison. I used the CMIs on my boat for several reasons. 1)because they were tube. 2) the allow me to put an air cleaner on the blower, 3) they are shinie and my engine needs all the bling it can get to distract the eye from my ugly bilge and wiring etc. My Corsican has CMI because no one makes them for a 351 Ford Cleveland and had them custom made for the boat, just to keep it original (Being a marine Manufacturer helps). My personal opinion is, not counting the CMI the two best looking systems are the Stainless Marine and the Dana.

[The Hedgehog]

A lot of us use the boat hedders for final tuning on the dyno. We start with dry hedders because of the plumming until we get it dynoed then final with the boat hedders. the problem with boat hedders you need a probe in each exhaust port. and most don't make a provision for them. Mark is correct in my opinion that boat tuning is the best way to go on the final step. His problem is his location it is usually at a low sea level and very humid, this doesn't help in Michigan. As for the Imco vs EMI vs CMI and the final ratings, CMI has several versiona from step tube to big tube. How many race boats use CMI and Stelling compaired to the others, almost all of them.
The Merc HP500, 575 etc all use CMI. No there is also a big performance hedder from Stainless Marine, Harding Keith Eckert, and the list goes on. So pick your poison. I used the CMIs on my boat for several reasons. 1)because they were tube. 2) the allow me to put an air cleaner on the blower, 3) they are shinie and my engine needs all the bling it can get to distract the eye from my ugly bilge and wiring etc. My Corsican has CMI because no one makes them for a 351 Ford Cleveland and had them custom made for the boat, just to keep it original (Being a marine Manufacturer helps). My personal opinion is, not counting the CMI the two best looking systems are the Stainless Marine and the Dana.

Very well said.

Unless you go to serious race boat headers, they are all within a few hp of each other. In that case, go for the looks!

I remember when we had this discussion before and Cuda finally said that he went with his Dana's for the looks. I thought that was a good honest answer.

[BigGrizzly]

You are absolutely correct. When we dynoed the exhausts hedders that week we found that up until 525 HP the HP difference was insignificant. We are not going into the stock crap here.

[mjw930]

Are you replacing them because they need it or ar your looking for a performance/bling upgrade?

If you need exhaust but are unsure of your future direction then I would go with the GLM's. I picked up a set for less than $600 delivered to my door for my peanut port 7.4L and they work as advertised. I actually did pick up 100 RPM on the top end, that was a pleasant surprise. They also sound different than box stock, I know they have individual runners (very short but still partitioned) so that's probably where the little bump in sound an performance comes from.

Here's where I got mine: http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=230275448105&refid=ebasicpower

http://bpi.ebasicpower.com/mm5/graphics/00000001/GLM59245.jpg

You can also simply add a SS riser to these if you decide later to do some cam or head work. http://www.cpperformance.com/detail.aspx?ID=308

http://www.cpperformance.com/images/620-32410.jpg

IMHO as long as your stay under 450HP these manifolds with SS risers are all you need and you end up saving money in the long run AND replacing your existing worn out headers.

One more thing, you will lose over 100lbs of dead weight off the back of the boat with this simple change. In fact, the rear of the boat sits almost 1" higher in the water than it did before the swap.

[zelatore]

Are you replacing them because they need it or ar your looking for a performance/bling upgrade?

Uh, all three?

I'm getting some rust begining to develop on the bottom of my manifolds, which never bodes well for the interior. Although I run the boat in fresh water, I believe it saw at least some salt water before I got it.

So I'm doing it becuase I need to replace the manifolds. Or will need to before long anyway.

The stock manifolds are hidiously heavy and ugly, and I always believe if you're going to the effort/trouble to take them off, you should put on something better while you're in there. So I'd like a little performance/bling upgrade as well.

And lastly, I already find myself googling words like "whipple" and "procharger", so it's just a matter of time before some extra goodies find there way under the hatch. So laying a basic foundation now is just another plus.

(I will NOT be the slowest boat at Powel next year! :smash:)

[22zxla]

my exhaust manifold should have been changed 2 summers ago, but didnt pull the trigger till this week. Ordered the emi thunder exhaust and they came today. Will have them put on this week and will report if any results. Not expecting much performance gains but think they will look good!