SSM 3 TO SSM6 conversion
 

How bad would this be? Would I have to change my engine heights? Transom is not cut yet for drives but exhaust holes are.

Is this completely stupid or worth looking at.

boat will be a lot happier with the 6s you can run a much higher drive height and the boat will get on plane easier also. have converted a number 3 top gun to a number 6 boat. if you have any questions feel free to call. Regards Dan

This is for my 36 widebody. I wonder if anyone else has put 6's on one.

Any differences in set up between wet sump and dry sump as far as engine height ect.

If the drives are plug in style the the drive height determines the engine height . If You are going drive line then I believe you have some latitude .
the 36 wide body is one of my favourite hulls . If you are going to convert you may consider adding a notch to the hull .
post your progress if you proceed with the conversion .
Rick G.

This is what I was trying to determine. My engines are plug in style and I wonder if I keep the engines at the current height how much would that change my current prop height and would it be optimal for a #6. I don't want to do any more cutting on the boat than we already have. This is idea is just due to an opportunity to acquire some 6's at reasonable cost.

I don't want to change engine height as I would have to have new tailpieces made for the headers.

I see Dan posted on this thread . He is a wealth of knowledge . In order to determine whether or not you can leave the engines where they you need to know if the 6 plug in transom assembly is similar in dimension to the 3 , secondly you have to determine the proper X dimension . This is where Dan will be invaluable . You have to compare the dimensions of the 3 to 6 drives . Its not as confusing as I am making it sound . I would guess that a 3 to 6 conversion will more than likely require moving the motors . But it is just a guess as I have never rigged a 6 drive boat Just TRS , 3 and 5 drives . Rick

My memory is a little foggy, but I think ssm 3’s are 24.311 shaft to shaft, 6’s 18.5”.
first find the x dimension of your current setup.
I think on your wide body the 6’s should be even to 1” below the bottom which will equate to 17.5-18.5” x dimension.
if it’s a factory ssm 3 boat, cig put the prop shafts 5-6” below the bottom meaning a 17.3-18.3 x dimension.

Thank you thats what i was looking for. My drives are too deep in my opinion i think they are at least 6" below the bottom.
https://cimg6.ibsrv.net/gimg/www.off...abd165a299.jpg
https://cimg9.ibsrv.net/gimg/www.off...cd77d8998f.jpg

Wow those are low . Rick.

I would put #5’s on extension boxes and call it a day. A lot simpler and the 5’s are pretty stout.

Put the 6's on in the same location. if they are too high its easy to space down. i have gimbals and fresh wet 6's sitting in my shop of you need them

I’ll have a pair of 1” ssm 6 spacers available soon

Thanks for all of the feedback. I am not mechanically inclined at all. I have a VERY vague understanding of this stuff and I am trying to get educated on what I can and cannot do. Also what I should and should not do. We are arlready WAY past what I intended and I don't want to get to much further down the rabbit hole but I have an opportunity to buy some #6 drives at a very reasonable cost. I had never planned on changing the drives as I don't want to spend the money to do so but I may be able to do some horse trading that makes this a possibility and I think an old school 36 with 6's would be kind of bad ass.

I looked at switching to #5's with boxes but with our basic calculations we were not going to gain anything. The angle of the shaft with the extension boxes was going to be too steep to get where we wanted to be. We are a little way away from doing anything, but we have not cut the transom for the drives yet. We have the exhaust holes cut and the new hatch made for the current engine height so it would be a ton more work to change it again............

Thanks again for all of the comments. I really appreciate your time and education.

Those are early #3's just changing to the crescent lower would bring them up a little, I would think #5's with neutral boxes or a 1 up would work fine, what kind of HP are you installing ?

Crescent and non are the same length

10-4 how much shorter are the 5's vs the #3's.....3 - 4 inches ?

the easy way of going from a number 3 to a number 6 and keeping the same engine height is to put the number 3 drill jig on the transom mark the crank center line and set the number 6 jig over the marks and see what needs to be filled in and go from there. As far as measurements the number 6 drive is about 6 3/8 of an inch shorter and the motor is about 1 3/4 of an inch forward of the number 3 set up. so if your drives are 5 to 6 inches deep than the number 6 set up should be fine I like to start with the drives at least an 1 1/2 above the bottom with a number 6. As was stated you can always go down but never up again. If you have any other questions feel free to call Regards Dan 949-646-9778

I told you Dan would have you covered.
RG.

Thanks Rick. Have done one or two conversions over the years. If you need to borrow the jigs I do lone them out no problem. Regards Dan

Wow you guys are awesome. Once I get up to the boat i will go and look at where everything is and see if this is even feasible.....then I make a deal on the hardware. If it looks to go that far i will be giving you a call Dan. Again I really appreciate the information. It's nice to get real information not just bs from people that have no clue and want to argue.

One final question do you think this is a good idea for this hull or not? Other options or just run what I got.

Motors dyno at about 750 hp and 800 ft lbs per side. NA 653 Donovans.

Interesting question . If You believe that the boat is a keeper then absolutely , remember in the end you will probably have more in the boat than you could sell it for so it needs the boat you are going to enjoy and run for along time . I went through that thought process before I put the notch and 5 drives on my flat deck . Rick

P.S. Go for it

The nice thing about deep drives is you can get on plane no problem and prop selection is easier. I crappy prop will get you on plane.
I`m even with bottom and there would be props that I`d spend 5 minutes burning a hole in the water and never get on plane. Diameter and cup will be very important .

I'm so far past the $$$thing. The boat will be worth about 1/3 of what I have in it.

Welcome to the club . Like I said that hull is one of my favourites along side mine, a 41 Apache and 43 Scarab flat deck.
Rick.

5.7”

He’s back!!!

Money wise, I'd be going with the 5s. Especially with the HP. Its not ridiculous by any means. I had 3A's on the old gun with 900HP, A ridiculously high X dimension. Moved motors up and glassed the transom twice. Crazy torque and all I did was change the oil and go boating with the 3A's. #5s are in that same category. 6's are a lot to maintain and so are the parts. Not to mention I have seen some sets of #5s on the swap shop priced pretty damn well.

Appears he's been a closet stalker!

I don't see how he has the time as much chit as he post on fb........:D

He's a closet "something".........????

Once again thanks for all of the responses. Can I put 5's on without boxes? Or would that put them up too high?

Sometimes I think we should just leave well enough alone, unfortunately this is all excess for excess sake. Gotta love it. I just want to get to the point where it makes noise again.


I am about to buy a 10k Sea Ray just to go boating..... I may also be getting a divorce with that 3rd boat. :D

Ironman. The fives work better with a box . The alternative is put a notch in the hull which is what I did . I am a do it yourself I have a thread on it titled “ how to put a notch in a flat deck “ pretty original eh! It was cheaper for me to put the notch than buy all the box parts . Enjoy amigo . Rick

Bruce would kill me at this point if I had him notch the boat after we just finished the entire engine bay. New transom, reinforced the bottom, stringer reinforcement all ground and ready for gel......

6" shorter

If it was me with 700-800 HP, stay with SSMIII or IIIA, 6's are tough but do still break and they are expensive to fix, 5's and even 4's would easily do the trick, but will need boxes.I thought about putting 4's and boxes on my gun this winetr with the parts I had here, veterans said at 800HP and under its not worth the hassle vs what you lose. In Lake Erie with that boat I think the speed gains of moving with that power will not be worth it to make the planing and rough water bite loss worth it, just my opinion. I been watching Frick battle this, Dan batte it, and even Cigrockets old boat is local does alot blowing out getting on plane. Brian Snyders boat at 80 with deep 3's is a BEAST in bigger and sloppy water, some boats like deeper drives even thought speed is not there, I learned if you want fast, go buy a Fountain, solid rough water keep the cig

Here is a couple charts to look at
https://cimg2.ibsrv.net/gimg/www.off...2abf4d33af.png
https://cimg8.ibsrv.net/gimg/www.off...34888c45dc.png
https://cimg0.ibsrv.net/gimg/www.off...4610febbd4.png

Hey Tim would mind emailing those charts to me they Are way cool . My email is [email protected] . Thanks
As for the box question , as I said earlier I put a notch and put 5 drives on my flat deck . I currently have 3 inches of spacers and the prop shaft is 2 & 1/2 below bottom . The boat planes at 3000 rpms in about 2 minutes or so . This summer I am going to take out 1 inch of spacers and see if I can a bit more speed without any loss to planing .
RG.

Rick, just sent

2 minutes?!

Thanks Tim.