Are you referring to chiro one apache. We were there.

pics of Apache with Arnesons

your correct Frank
 

Right now the drive are high for #3a's about 1 1/2" below the bottom, boat loves large dia props & runs fastest with 3 blades. I agree we would go faster with #5 drives. We are racing in opa class 3, a 95 mph max speed before breaking out, right now we are running just shy of 100 with a slip factor of 9%. We are pleased, next time out we will have our new motors.

When I first put them on the boat I had them rotating in and the boat got a little squirelly in choppy water running fast. I changed them to rotating out and the boat was a rock in the water but went slower. I have learned alot since then and have figured out what the boat likes for setup and props rotating out. Now I am too lazy to switch them back to see how it works. Overall I am very happy with the way the boat runs and these drives don't break.

I like the weight reduction of arnesons, there proven dependability, they would lower the center of gravity

5's would be the easiest upgrade however, there are very few 5's out there as well as parts

Why does this boat have so many exhaust pipes ? Does it have Lambo motors ? Or is that something else

Yes

our gimbles are mounted on the high side but not as high as a 5 or 6 would be. Our apache is comparable to weight of starchaser and predator. Looking forward to the new motors next year:)

Gimbles should be mounted lower with a 5, crank centerline to propshaft is 6" shorter than a 3a. Part of the advantage of going to a 5 is keeping the engines low and propshafts high. My x dimension is 21.750 to have my propshaft about 2 5/8 below the running surface. If I bolted a 5 on it would be 3 1/4 above.