28 pitch thru 32 pitch, same speed

[BDMar]

The boat has shown the same characteristics no matter what engine he's run. The problem is in the boat and setup. I just pulled out 5 different dyno sheets on various blown engines ranging from 509 CI to 572 CI. Everyone made at least 100 HP more at 5300 than at 4500. It is possible that their is a mismatch in his engine combo.... except that all engines react the same way.
Look at the bottom, look for hooks in the running surface and strakes. Run a straight edge off the bottom with the propshaft parallell with the bottom and measure how far below the bottom the propshaft is.
It sounds like you are not getting more lift as the speed increases and it is hitting a wall at 70.
EDIT: One thing that sticks out is you say "large cam".... how large and what are "good heads"?

[spectras only]

Your Arriva is the older style and it may have a hook that's causing it hitting the wall @ 73 . I wouldn't push that boat much faster . The newer Arriva was tooled and refined to
be a better performer
http://www3.telus.net/spectrasonly/1996%20Arriva.jpg

[DMOORE]

The application is a 1989 Arriva open bow boat V bottom
BTW, I always liked the look of the Arriva. There was just a 90 for sale here in San Diego. A buddy was looking at it but couldn't come up with the cash in time. As for measuring the prop shaft; measure from the bottom of the keel (I'm assuming there is no pad) to the center of the shaft. Remember, these boats were set up for pleasure cruising, and good on plane performance, not top speed. Because of this the drives as set quite deep.My guess is that it's buried. Thats why even with a big prop, the boat still jumps on plane
Darrell.

[ghittner]

I've always been very suspicious that my drive was way way way too low.
How do I take my measurements? Thanks.
OK, propshaft is 9-10" below the bottom of the V.

[DMOORE]

OK, propshaft is 9-10" below the bottom of the V.
HOLY smokes! that thing is buried. On a vee like yours, you would want about 6-7" below, for performance. All of that drive in the water is really holding you back. If it were me, I would go with a 3" shortie, then if it's TOO short, you can add a spacer for cheap. I've seen ya on the oso site also, try the ads there, ya may be able to pick up a used one for a decent price. If ya need a hand I'm only an hour down the road. Sometimes an extra set of hands really helps.
Darrell.

[ghittner]

Your Arriva is the older style and it may have a hook that's causing it hitting the wall @ 73 . I wouldn't push that boat much faster . The newer Arriva was tooled and refined to
be a better performer
http://www3.telus.net/spectrasonly/1996%20Arriva.jpg
I was always under the impression the earler Arrivas were a better tooling and stronger manufacture due to the fact that Bayliner bought them out in the early 90's. I was told quality and strength were compromised on the later ones because of this. The hull as I compared it never changed only the manufacturing quality suffered later?????

[ghittner]

HOLY smokes! that thing is buried. On a vee like yours, you would want about 6-7" below, for performance. All of that drive in the water is really holding you back. If it were me, I would go with a 3" shortie, then if it's TOO short, you can add a spacer for cheap. I've seen ya on the oso site also, try the ads there, ya may be able to pick up a used one for a decent price. If ya need a hand I'm only an hour down the road. Sometimes an extra set of hands really helps.
Darrell.
I always felt as though it had a parking brake on when I gave up the throttle. I have to trim this boat so far up it's unbeleivable. What would be the best overall depth considering stability as well as speed? At what point do you give up the excellent handling characteristics of this boat? I will post pics for you all to look @ later today, please all of you, take a look. Thanks
Darrell, I appreciate the offer as I've never pulled a lower and have only pulled the entire drive too many times too count.....

[ghittner]

Here You Go, The Hull!!!!

[spectras only]

I was always under the impression the earler Arrivas were a better tooling and stronger manufacture ?????
I'm not so sure about that . The newer ones were rated for more HP .
The earlier ones were rated for the 330 BB as max :idea: .

[spectras only]

What would be the best overall depth considering stability as well as speed? Thanks
Your drive is definitely too deep down as dmoore mentioned . It was meant to be a runabout , not a speed demon . 7" would be much better , and you could go shorter .
BTW , I like the older models compared to the new ones that are a little overdone in styling .