F-2 Speedy

You had to install the SCX ITS helmet for the set up correct.

Lucky Strike Jr

You’re right, I forgot about Todd’s old Fire Escape.

If your 39 gets up on plane pretty good now, and your whole point of this is to have a beefier drive....I would go as IMCO recommends with SCX Upper and Sportmaster Lower. The X shouldn’t change. If it is harder to get on plane you can always put a spacer in. You can always swap out lowers and discussed earlier with SCX Upper.

Quinlan-what gear ratio are you running with your SCX’s?

endeavour32

I'm running 1.50 with my XRs.

Lucky Strike Jr

Sorry, I was asking Quinlan. I edited my post.

MAXIMUSXXX

Sounds like Quinlan and I are running close set ups. Mine is a TS 725 hp and 760 Trq. Running SCX’s uppers with SC lowers (-2” w/ 1.34 ratio). Already on second lower gear set. Both motors are out getting refreshed. Just order Drive Guardians hoping to keep from eating up lower gear sets. Bravo I w/ 31 P. I run in Gulf of Mexico and the waves can be a bit unpredictable and it’s hard to keep props in water.

Quinlan

My regular props are 32 Bravo 4 blade. I really thinkg I have not trimmed the drives out enough as I did w the 5 blades because it was end of season run when I was testing them incase something Broke. I was testing with a friends set of Herrrings.

1.50 gear sets.
WIll be back on the water Soon- Carter?? lol
Started replacement of all gages and dash panels this winter- then this Dam Virus and switches were coming from China-
So he is putting it back together with what I had and splashing Soon! We did take out the spacers in the drives. Among several other things .

315duramax

Let me ask this, what is the cost on the SCX 4? new or used?

Is your boat setup on twin drive shafts or is the read motor plug in?

If youre already double drive shaft, i would find a pair of NXT or 6's and hang them off the back. Of course the imco option is total plug and play, but for that investment, i would think a 6 or nxt would be better option. What is considered bigger at this point? an NXT or an SCX4?

KWright

I ran a set of the first scx 4 on a fountain 35 side by side. The bullets are huge. They resigned the skeg to try to offset the drive trying to ski off the bullet. If I were to do it again I would use the scx upper and dual downshaft lower.
Remember if you have a staggered setup the input shaft on the forward motor will be the weak point. Seen a few twist with aggressive setups. Maybe consider drive guardians?

F-2 Speedy

Both of these drives require a transmission which he doesn't have.............its a bravo boat,

endeavour32

I have considered the NXT, however it is a lot of work to convert vs an SCX. Plus the NXT transmission is a weak link when you get over 700 hp, and if I had to guess, in stock form, the SCX is stronger. Yes you can replace the NXT transmission with the BAM conversion but that is $15k plus. If I could find a good deal on an NXT set up, I would consider it. As far as costs go, SCX-4 used maybe $22-23k. SCX uppers used- maybe $16K.

The Six is just too heavy. They only made a few 39 with 6's. The Bravo and NXT boats are better balanced. Plus with the Six, you would have to move the engines from a full stagger to a short stagger. There isn't room to run a full stagger. I want to keep the engine low in the boat, so anything with a velvet transmission is out. Otherwise, I would have installed the Arneson setup I had. That would clearly be the best option, but that is way too much work!

So the best option for this boat is, SCX or NXT. If I leave the engines as they are, maybe Bravos with Drive Guardians.