Fuel flow meter.

Boats that go on long trips have these for a reason and not just $$$ for gas.

Newer boats have that on smart craft, how do they work on older motors? sorry, never really have seen them.
Assume they read flow on fuel rails? Gauge on dash or just on motors? I am really more interested in finding my sweet spot for efficiency.. I normally just run 3800 @ 50.....

Type in Fuel Flow Meter into a search engine.

Oh, if you have a return fuel line (All EFi...some people do with performance carb set up) you'll need two meters and do a meter A minus Meter B set up, as Meter B will be measuring return flow which of course is being returned ie: not being used by the motor.

Oh, if you have a return fuel line (Most All EFi...some people do with performance carb set up also) you'll need two meters and do a meter A minus Meter B set up - some Guages can be progeammed to show net reult vs having to get two guages), as Meter B will be measuring return flow which of course is being returned ie: not being used by the motor.

Check flo scans website. All the info is there with diagrams on how to install. A little pricy but one of the better ones in my opinion. You can get 1 gauge that will monitor both motors. In my formula I installed it. It had 2 switches and 1 button installed with the gauge. The switches were one from port to stbd and one from rpm to fuel flow. The button was basically a reset for total fuel burned. You run te boat and test total fuel burned. When you fill back up you do the calculation and adjust dip switches on the back of the gauge until you are damn near perfect. You will then end up with accurate burn rates.

Heads and cam make the engine the best match will make best results... I am firm believer in custom cams... I have always ground my own for the combo...

You may have big tq numbers but them numbers under full throttle not part throttle so it really don't matter... Of course you want a strong solid tq curve especially to get old heavy boats moving....

Tim when did you get a cam grinder??? Lol

Haha he's called Cam Motion! Bob does grinds for his boat cams I guess also...I don't believe in off the shelf cams unless you are doing simple combos... All my car stuff has been custom with great results boat engines were custom but going bigger this year so either grinding new or buying a set mild thunder kjows if that sound perfect for my combo

Back in the 70's, they used to install "Economy" meters in cars. I remember as a kid our family car was a 1975 Bonneville. In the instrument cluster, it had the "economy" gauge. It started out in the green while cruising down the highway. Upon acceleration, it would swing towards the red. Harder you accelerated, further into the red it got. lol, all it was, was a vacuum gauge.

High vacuum=low load
low vacuum= high load

To get back on topic though, there is something to be said about having an engine package that operates efficiently in your cruise range. Like I stated earlier, you wouldnt want to slap some huge 345/360cc port heads on a mild 454 engine, with a cam that would make peak power at 7000RPM, in an engine you don't plan on spinning past say 5400RPM.

There are alot of options though nowdays, as far as engine combinations, that give you a bit more flexibility. We have great valvetrain components available, that will allow you to safely turn that smaller CID engine, a bit faster to make up for its lack of CID.

I'll use my friend Joey's engines we recently built up as an example here. He had 522ci shortblocks to work with. Really nice components in them. He had Lunati Signature series blower crankshafts, oliver connecting rods...He like any of us, wanted to make good power. He had his sights on 1000HP.

Him and I talked alot about his build options. At the time, he had Edelbrock marine performer heads, and was purchasing 1071 blowers and intercoolers. I just knew, his edelbrock heads were not going to allow him to meet his goals, at least without an insane amount of boost that is.

A couple of his buddy's told him he really needs to go to a 4.25 stroke, to make them 555ci. I disagreed, and thought he could hit his goal, but it would take the right cylinder head/cam/boost/rpm combo.

Thats when I recommended he get in touch with Bob Madera, and look into some AFR heads, cam, etc. After working with Bob, Joe decided to go with the AFR 315 cylinder head, Bob did a cam for him, and the right valvetrain components to go with the setup.

When it came down to dyno day, the results were what we hoped for. The engines made their target number, within the target RPM/BOOST levels. The torque was outstanding as well.

Now just for comparison purposes, or to go deeper into all this. Our other buddy had recently dyno'ed his blown combo. His was a 540ci, 345 Dart heads, also a 10-71 blower (its what he had to work with). While this build had the cubic inch advantage, it made less power. With both engines at 8lbs of boost, the smaller 522ci, made 37 more HP at 6200RPM, and quite a bit more torque thru the rpm band. Same dyno, same dyno headers.

One would think that the larger engine would have made more torque, along with more power. I was really surprised at the torque production from this 522, not only was it a very flat curve, the numbers were really great for what it was. The key was the 522 simply had a better package. With that being said, the iron headed 540ci making 893Hp at 8lbs of boost, is/was nothing to turn you're nose to. Its just a comparison. But if they were both 540ci, Joey's engines, would have made around about 70HP more lb for lb of boost. Keep in mind those 345 Darts, are tremendously better at moving air, than a GM rectangle port casting. So, if that 540ci deal had a set of GM heads, that 37HP gap, probably would have been closer to a 137HP gap. Point, theres more to building a good package, than simply throwing cubic inches at it. Same goes for N/A engines as well.