No Mufflers.

The same fuel pump, filter, ignition, everything as on the dyno except the exhaust.

The cam is about the same or a little more than a stock 454 Mag.

Regardless, it perfromed on the dyno, yet not in the boat....

I need to figure this out as this is going on 3 seasons of running the motor and I still don't think its all there...

Where is your timing set?

Where is your dyno torque peak number and HP peak number?
What prop are you using?
You could be torque loading the drive which would hinder your RPM.

Las, I was wondering the same question as was posed here. Could we be losing considerable HP on my set up with those Gils over the headers you use on your Dyno ?? 50 hp loss could be costing me 1.5- 2 mph. and you know how I feel about those damned gils

Otis, I lost a motor in my Fountain because of internally leaking Gil manifolds.

I'd give Too Old a call and pick up a set of CMI's pronto! (he's got 'em in stock)

How would you feel if you ruined your new Mesa Balancing mills because of substandard exhaust?

...just my .10

The cam has been installed at 110 Degree Intake Centerline.

Dyno Numbers:

RPM HP Torque

4000 542 711
4500 603 705
4800 625 684
5000 626 659
5300 642 635

It was putting aout good HP and torque at 5300 RPM on the dyno, yet won't get there in the boat. I've tried many different pitches of prop with minimal results.

Thanks for the help!!

Is your fuel system up to the task? Are you running a boost referenced fuel pressure regulator? What are you running for a fuel pump?

Is she getting enough fuel? Have you checked the fuel pressure? Does the fuel regulator add fuel pressure correctly as boost increases? What size is the pick-up in the fuel tank? Size of fuel line? Size of fuel tank vent line? What type fuel water sep. filter are you using?
Is the intercooler mounted in the same location with the same hoses and elbows as on the dyno?
I saw the pics of your install, nice job...but I noticed you have several bends in the air hose from the IC to the intake. You may be able to fit a single 180 hose or two 90's and you'll free up some power.



Like this M3 set up:


Do you get any belt dust after a run?

Your TQ curve peaks way too early and falls off. At 5000rpm you are off 50 lb-ft TQ and at 5300 you are off 75 lb-ft TQ! You need a bit bigger cam and a flatter TQ curve. With a centrifugal SC you should see almost a flat TQ curve and in your case around 700lb-fts. What does your boost curve look like at the different rpm's you posted above? You should be building boost with increasing rpm. If not, I would check the belt for slippage. Look at Tomcat's 500EFI dyno and boost graph. That is what I am talking about.

I just spent $2800.00 on Manifolds and it looks like my custom dry pipes are going to run another $3000.00...So, Im stuck with the **** Gils. I was against Gil, But Las insisted due to the situations we had while installing. I purchased the Danas and had them shipped to Mesa, but Las had them returned because he doubted they would work. He is the man holding the key to the 1 year warrenty on the 700's .. So I listen to him. Dont like the Gils though, because of the leaking