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Changed the design of my adapter plate and tuner around a bit to adapt a 56ci powerhead to a 2 cylinder mid. First the adapter plate is bolted to the block and then the mid is bolted to the adapter plate. 2 cylinder mids are way easier and cheaper to find and they bolt directly to the boat verses that shitty clamping system on the stingers. Hoping to make a prototype soon. Also hoping the 2 cylinder housing is strong enough.

is the 2 cylinder shaft and gears strong enough for the 56 cu in ?

As far as i know the gears are the same as a 60 or 70 3 cylinder as long as its not a nitro.

aaah I see.
good idea to have the 2 cylinder mid and gearbox as like originally said much easier to find stuff.
will definitely be watching this project.

2 cylinder gear case has different splines. 3 cylinder had the same bolt pattern. Was intend to use with a 3 cylinder case.

Kevin

this sounds a nice project.
hope we get lots of pics of this while being done
.

I don't think the SST-60 style tuner will work on the 2 cylinder motors. If so, why make an adapter plate that allows a 56.1 cid to bolt up to a 45 cid mid? The mid sections are the same, but with different clamp bracket, & tuner. The gear ratio of the 2 cyl. Nitro is 2.42:1, while the 56.1 cid is 1.86:1. Yes, the splines are different (4 on the old 56.1 & many on the 45 cid).

What is the advantage to do this project? Help!

3 cylinder mids are getting expensive and hard to find. 2 cylinder ones are cheap and more of them around. 2 cylinder ones also have a nicer clamp bracket. The 2 cylinder mids are not the same. They are about 3/8" taller and have a different bolt pattern for the 2 cylinder powerhead. I have no plan to use a 2 cylinder gear case or a 2 cylinder powerhead. Just a conversion to adapt a 56er to a 2 cylinder mid. I already have the design for my regular adapter plates so it wasn't a bid deal for me to change the design around to make it work. If someone has to buy a mid and an adapter plate, this will save them a few hundred $

I noticed after putting the photos up that I need to change the steering mount on the adapter plate to bolt in from the front and not from the top as you won't be able to install it after the plate is bolted on to the powerhead. The 2 cylinder steering arms have threaded holes and have the mount bolted to them first unless you were to modify the arm. Just easier to put some holes directly below the steering arm holes and bolt it from the front. I will put up a picture up later to show what I mean.

an slt guy (detroitwhitey on brf) tried the 2 cly clamp bracket on 3 cyl mid. the clamp bracket broke, but may have been a fluke.

Good to know. I've heard of a few people trying the 2 cyl clamp bracket. First one I've heard of breaking though. I hope it was a fluke. I think I'm going to try this all on next year's boat.