pantera38

Hi All,
I've read many posts on setting X dimension, but still having a hard time figuring out what to do for my specific application.

I'm planning on installing bravo drives(lwp) on my Pantera that was originally rigged with #6's. The engines are staggered and jack shafts will be used to connect to both drives. I'm planning on having an extension box made that will adapt the bravo to the #6 cutout on the transom.
The transom angle is 13.4 degree and the transom has a 10" deep notch on the bottom. The attached picture shows the current cutout for the #6 and the drives are on 18.5" centers.
Also the height of the notch at each drive center line is 7".

Now.... how would I determine the proper X dimension?

I'm sure I need to take into account the transom notch, but how does that affect it. I've also read that for each 12" the drives are set back the drive height can go up 1". Does the notch transom enable the extension box to be shorter in depth (ie. 6" vs 12")?
I can have the box fab'd to any depth as well as have it layout with a "neutral" setback if needed.

Anybody else ever go thru a conversion like this?
Lou

Cord

Yes, the extension box does act like a setback, so you can raise the x by 1". But raise it to what? I really don't know what your boat needs, but I'm thinking that it would be around 3" below the bottom.

Question-why are you changing from #6 to bravos? It seems kinda regressive.

pantera38

Well I bought the boat without engines and drives and the budget does not allow the high $ stuff. So the bravos are the drive of choice for now. That's one of the reasons I don't want to re-glass the transom - keep the options open down the road.

BenPerfected

Where was the prop shaft on the Six Drives in relation the bottom of the boat? It it was effective, that might be the place. What is the ideal x-dimension on a 38' Cigarette? After you get this input, the answer should get you in the range. Martin Marine can be a good source of info. My experience would suggest to error on the high side and then use spacers to go down if necessary. If you expect to end up in 90 mph top speed range, you might consider the Merc Sportmaster or IMCO lowers. I would hold the drive shaft angles to a max. of 2 degrees. Great project!

bob

I can tell you that on a 39 Sutphen with the Merc ext box and #4 I am 1" above bottom and could actually go a little more if that helps.

Bulldog

Pantera-
If you don't have the drives already, and are considering more than 500HP per engine, you might want to think about #3 or #5 speedmasters. I've seen complete twin #3 setups with transom assy's, etc for about 12-15K . Your existing engine mounting points should allow you to use the Speedmaster/transmission setup. Do you have exhaust/headers, and other stuff?

Sounds like an interesting project.

Good Luck!
Bulldog aka Ronnie

Raypanic

Call Pantera 1st. 2nd Look at some one elses Pantera. FYI: On my boats (which all 3 are different) at level trim, the c/l of the bullets on the bravo drives are from 1" to 3" below the bottom of the hull. This is also inline with the hull not the very bottom of the point of the V.

Griff

I would mount them deeper than than the #6's were. Maybe an inch or more. The #6's with the tranny's would have weighed more than the Bravo's will and would have kept the stern down more. Also, wasn't your boat originally set up as race boat?? The X's would have been set pretty high if this was the case also.

You can always adjust your propshaft height with drive spacers or shorty drives, but that can get expensive. Spacers run from $600--$850 each.

With the hole cut for the 6's, you should be able to determine where the X was originally set. I would also give Jo a call at Pantera. He probably has the specs and could offer some advice.

Blackhawkdn

Who is making the standoff conversons for you, I have a 36 daytona set up for # 6's , going to use Bravo drives on the boat

pantera38

thanks for the suggestions.
I plan to speak to Jo at Pantera today.

Griff - yes this was originally set up as a race boat. How can I determine the X from the original #6 transom mounting holes? Would I need to get a template for a #6 to get that info?
Where could I locate one?

Bulldog - already have the power and picking up the drives this week - no exhaust or headers yet. still searching.

Blackhawkdn - making the box with a machinist/fabricator at work.
Due to the proximity of the 2 drives, the plan is to make one box which spans both drives. I think this will enable a stronger box, make the installation simpler, and should add just a minimal amount of excess weight. As soon as I can figure out the drive location, we'll finish up on 3d Solidworks model of the box and start cutting material. Where are you located in Jersey?