tssteph,

It would help, but price the stuff to add them,

new custom tailpipes... high dollar
drive shafts ... aren't cheap
drive shaft kit for the transom assymbly and the engine kit is about $1k i think.

this is before you take the time to redo your whole rigging in the engine well.

quest has the lightest 3100 ever built.....

Well, my are moved forward and I have a 2in. spacer in my drives. Planes off instantly and I barely have any bow lift. Boat is in total control and does not feel loose! But come this summer, I will be taking my spacers out and I will be installing 30Pitch 5 blade bravo's. so god knows how the boat is going to react when I do this! Art DiNick from AO has my same exact boat but the only difference is that he has boxes. I had a two hour conversation with him. My boat hits a 138 MPH with PFaff 900's, he hits 142 -145 MPH or so. He told me to add boxes with a 1in. spacer in the drives and add a tunnel tab and I will be all set! He definately said I need a tunnel tab as well. Our hull design with the tunnel we have, the air flow I guess gets blocked or something, that our hulls around 110-115 get dragged by that triangular V in the top of the tunnel and it drags the boat down. He said the Tab will help create enough pressure to get the tunnel 100% air flow once the boat hits the 115 or so mark. I started to think about it and he's right, my boat will sit at that speed for a sec or two and then she will start to increase to her top end. The other bizzare thing is that I absolutely have no porpoise at all what so ever!

Well, my are moved forward and I have a 2in. spacer in my drives. Planes off instantly and I barely have any bow lift. Boat is in total control and does not feel loose! But come this summer, I will be taking my spacers out and I will be installing 30Pitch 5 blade bravo's. so god knows how the boat is going to react when I do this! Art Dinick also told me I need boxes and a 1 inch spacer when I add the boxes along with a tunnel tab and I'll be all set! Im hitting 138 currently with my set up with 2 people and a 1/4 tank of fuel, I can just imagine what I will hit with Boxes and 5 blade props hittin the surface! I say move the motors forward, it eliminates bow lift and gives the boat more stability with the CG ratio. If you do this without drive spacers, I dont know how she will be, but I have 2in. spacers with 4 blade 32 bravos running 1.24 gears and shes a f???ing rocket with PFaff's 900's. If you want you can call me and I will give you all of the details.

What RPM are you running at 138 MPH?

What do you think about using the imco torsion shafts (from an extension box)to move the motors forward 12"? You could make a new rear motor mount and leave the drives on the transom. A couple of stainless tailpipe extensions and move some lines around.

The torsion shaft is not riding on any bearings in the extension box, it's only supported by the gimbal bearing and the coupler, so what would it matter if the motor is moved instead of the drive. A drive shaft guard could be fabricated to go from the transom assembly to the bellhousing in case of a failure.

She spins about 5900 RPM's

Before you go making any decisions on a Tunnel Tab (or any modification to the tunnel), give Sparky a call at Vicious. He advice and wisdom could just save a life-------yours.

With all of this talk about motor position/placement, keep in mind the original design of the Chris Cat and the use the speedmaster drives. I can't think of anyone who would be more knowledgeable then George or Rich on this subject matter dealing with these hull designs.

mine has a tunnel tab and it works good mine spins 6700 rpm 1.36 gears 32 pitch hydro's labbed no diff rings it pulls hard