blue thunder

All great input. Is your engine set up to make max hp at 6000rpm? If not you should definately reprop for max hp rpm. If it is making max hp at 6k I think you would get a pop from true length headers. Etops of course are not that and in fact I'd rather run the SM manifold. But a KE, stelling or CMI true header would help in my opinion with the proper collector and maybe reduced water flow. Scavenging at those rpms is certainly possible. I saw a set or two of stellings for sale today on one of these sites for $1600.

Panther

Stainless Marine Manifolds and the E-Tops are almost direct competitors. They've run dyno tests and it's shown that the HP difference on a 500 hp engine is minimal and in some cases the SM's make more power.

What I would look at is having SM exend your existing taipipes out the back of the boat or at least to the inside of your transom. You can probably get that done for a few hundred bucks. Especially if you're going to make more power it would be a good idea to have water enter your tailpipes as far back as you can get it.

I run 800+ HP with SM Manifolds and 4 1/2" dry tails. I "used" to run Elbo tops with dry tails and I saw ZERO difference going from the Elbo Tops to the SM's...

endeavour32

iTrader: (4)

I picked up a set of e tops today if they fit I'll keep them, if not I'll modify my SM elbows to run the pipes out the back. I think Jerry quoted me $300 or so last summer to extend my elbows... I didn't want to be down for 2 weeks so I ran it with the standard elbows. Even though I didn't have an issue RMBuilder designed my cam for dry to the tip SM manifolds so thats what I want on it...

Here is a great chart on the manifolds someone posted a while back (I modded the chart to only show a few options).... From what I can see the etops have a fair more torque than the SM but your all right HP there very close. In the midrange the CMI seems to have an advantage as well.

I checked on the Stelling listed on here. I was about to pull the trigger on them until I called stellings and they said that model won't work on a bravo set up.. There for #3 and #6 drives.

As for the engine its designed to run at 6100. Thats why I'm trying to pick up a few hundred rpms. I'm kind of at a loss what to do for that as I really didn't skimp when this thing went together. I was going to try and do it on the cheap but everyone said do it right the first time. So thats what I did. I know I can get Bret tweak the prop but first I want to squeeze everything I can first out of the engine.

As always thanks for the input so far.

blue thunder

Can you provide details of the engine build? Cam, heads, intake, compression.

Here are some bravo stellings if still available...

http://forums.boatfreaks.org/showthr...215#post260215

endeavour32

iTrader: (4)

Specs
439 cu (427 crank)
10:1 CR
AFR CNC'd 265 oval port head
cam 234/240 dur .63/.61 lift
Pro Systems 4150 carb 830 cfm
weiand stealth intake
Morel lifters
Scorpion endurance marine 1.7 rockers
Crane Ignition

Bodi

Is that motor in the 242 Formula? How fast are you running with that HP? I have a 88' 242 with a 454SC clone. All I can get is 54 on GPS at 6,300'.

Just wondering what top speed you get with bigger HP at lower elevation.

endeavour32

iTrader: (4)

Yes its in a 242. In chop I can get 64.5 on gps. Thats with a 21 Mirage @ 5900. How many hp are you putting out?

Griff

I highly doubt you would see any gains going from the SM's to CMI's. I switched from Gil's to CMI's on my 525SC and saw no gains in power.

articfriends

iTrader: (1)

Don't waste your money, I run Stainless marine 3's, they aren't flashy but I get no reversion and motor makes over 1000 hp, Smitty

blue thunder

Have you tried different props to bring the rpm down? It seems to me with that engine youd be better served in the 54-5600rpm range. The lower cubes throw me though so I;m not sure.