Full Force

Correct, as you know... if I see a 74-75.... at whatever RPM it is... with existing props, I will be very happy... that was goal from beginning and still is now, I never set a goal to be 80 or more because thats just not gonna happen... would be cool... but not likely with current parts. A 75 mph Mistress isn't doing too bad... at least the engines are good for 950 ish with some boost

Baja8808

Were these numbers made with using the cyclone shorty headers?

KWright

Yes and fully dressed with flame arrestor.

bigboat28

Gils are better than those header type exhaust????

chancer540

I dont understand why you would move down in cubic in. and expect the boat to be faster, when its cleary making a lot less TQ.
For christ sake look at your torque that 565 made from 3000 to 5200 compared your 540. It aint no wonder
the 565 pulled hard in your boat. You are going to have to out produce the torque your 565 made, not just move
your 540's TORQUE an hp up in rpm...

"So new engines made more HP, but had less TQ, boat was a SLUG and would not even meet old speed let alone faster.."

saying that right there alone says you need ALOT more torque. I would think TQ alone is quite a bit more important than hp...your dynoes prove it.

Your 540 made more torque only "a couple a hundred more rpm" (540 more cam) more than your 565. So just moving your 540's powerband up in rpm alone isn't going to increase speed, unless your making considerably more TQ than your old 565......

But who knows, hopefully the new mills are making some crazy TORQUE and carry your boat well......

MILD THUNDER

My boat went from 88mph to 96mph, by adding power from 5000-6000rpm. I actally lost a bit of torque in the 4000rpm range. I am pulling the same props to 6000-6200 now, instead of 5500-5700 .

It doesnt "carry" any different. It just goes faster

mike tkach

it seems that the word TORQUE confuses people sometimes.big torque at 3500 that falls off at 4900 will not push the boat the same as an engine that makes peak torque at 4400 and carries it through 5800 rpm.the wrong cam can KILL the torque curve.

chancer540

Tim has repeatedly said his old 565's were 2-3 mph faster. And when you look at the differences in the dynos it makes since.
If he would of put his 540 cam and afr heads on his old 565's i think he would of bettered his best mph. His 540's aren't making near the power his 565's were.

How do go you from old motor making X amount of hp and new motor making 34 more hp and go slower?
Could it possibly from old motor averaging (626) tq 506 hp and new motor only being (603) tq and 501 hp.

I'm sorry, but from the first time when i seen Tim went from the bigger cubes to the smaller one's i just couldn't figure out why.
Especially in a N/A engine. Boosted engine totally different animal. Especially when adding more boost and making the kind of changes like you have made.
Very impressive......

Full Force

Well to start with, when I was guided my BOB M to buy my parts I went 540 to keep cylinders with room to fix something later if needed, so we did not go that route, Bob swore up and down and back and forth I would build 540's that would SMOKE my 565's all day long... in his exact words, he talked the game and sold me parts, this was the result... Had I dynoed before they went into the boat the first time maybe my expectations would have been different... it is what it is, I am fixing that now.

Full Force

Show me whgere I said 2-3 mph faster MANY times?? never said one time...why are you trying to poke a battle? boat went 73.7 with old power once, new power 73.2..... yes thats 2-3 mph? ok thx for input.

as far as CI, I explained that in other reply, thx Bob M...