I’m thinking of purchasing a 27’ avanti. It had an Arneson drive on it. I have a blown 565 BBC. Should I put a stern drive on it or an Arneson ? This boat will be strictly go fast. It’s been gutted and I gotta build it up. If stern drive is the decision, anyone know of any patterns or info as to locate the x dimension properly for a stern drive setup ? I’ll be putting a new transom in it so the option is wide open at this point.

What kind of power ? might determine the drive choice, the surface drive would be the best choice for all out speed

The power is a 565 with an 8-71, 2 AED 850’s a bullet cam and brodix BB3 extra heads. Should be around 900 pump gas motor. Still waiting for the machine work to be finished at Bitner automotive in Trenton nj then the dyno will tell the real numbers.

That hull is a real old school wave crusher. That said, it's going to take a ton of power to get any kind of speed out of it. An Arneson will be faster and with 900 HP, a stern drive normally used on that size boat holding up to that much power (and weight) is doubtful. Even with an Arneson though, you'll be surprised who will blow right by you with less power.

That boat will not be happy with an arneson. avanti's need all the help they can get with bowlift.
Ours used to have twin small blocks with KAAMA drives (very similar to arnesons)....it was a bow heavy disaster even with the twins.
Now with a single 525HP and XR drive its just as fast.
With 750HP it ran low ti mid 80s. Thats all that hull wants. If you want to run 90+, get a different hull. You'll thank me later.

We wound up with a 1in spacer in a stock drive. We mounted it where Dennis told us, but couldnt get it to hook up. Ill find the notes and let you know.

Thank you for the response team sarris. When you say you had a hard time hooking it up, what exactly do you mean by that ? Thank you for searching for any notes my concern is getting that drive in the right spot Look forward to hearing from you

I have to agree with the master there on a Bravo giving more bow lift than an Arneson. Only one problem though. 900 HP in front of a Bravo on that heavy hull with anyone less than Jason or Johnny Saris on the sticks is a recipe for shrapnel.

At the end of the day, that is the reality/outcome of building big power in an old hull that was never engineered to go that fast...... but reality is sometimes like sticking a pin in a power outlet - people will do it thinking they will get the outcome they want.

Sometimes it's simpler and safer to look for the right hull vs. cheap and available - my $0.02

correct. and the "surface drive is best for speed" claim is completely false on this style hull.
An IMCO SCX would be fairly reliable in front of 900HP. But that same 900HP would push a 27 Kryptonite well over 100. That Avanti will become uncontrollable in the high 80s