90 Degree Gearbox

I think the main choices would be 1) a bevel gear (low ratio and somewhat noisy), 2) a worm gear (higher ratio but quieter), and 3) a hypoid gear (intermediate ratio?) I'm not versed on all possibilities, so this is just a start.

You haven't told us what size (283,305,327,350) or how much horse power/torque you're expecting out of the chevy mooring block. This has a bearing (pun intended) on what you need to use.

Your going to be limited on the physical size.

May I suggest you use a shaft drive bike driveline ala Yamaha XJ1300 or Honda leadwing. This would allow you to use chain/belt drive from the back of the flywheel to the driveline. the bikes are pretty heavy with grunty motors so it may hold up to what you want.

Alternatively with some requisite engineering you could use a differential from a BMW 5/6/7 series as they're an independant rear and fairly compact. Maybe a Mercedes Benz diff is also a candidate, it would have to be from a V8. You will need to "lock" the diff but that's relatively easy done.

I have seen this done before, I'm surprised that there isn't a kit, you might want to google chev powered harly or something like that...

just a stock 350 and i have to find out the tourq and hore of it.

here an idea. Take the center section out of any rear wheel drive axle Ex:Ford 9inch, Dana 30 or what is small enough for you. Choose the ring and pinion gear of your choice in accord of the chain/belt drive sprockets of your finial gear ratio.

Install a spool or "Lincoln lock" the diff gears. Cut, cap axle tube on the side not needed and no axle in that side that the reason for the spool. Cut the other side to length needed keeping seals and bearings, with axle modded to accept a counter sprocket.

Direct couple the trans output through a u-joint into the diff u-joint "the trans half of the u-joint on one half of the cross, the diff on the other half of the cross".

Install appropriate mounting points to diff. to frame in accord to how the rest of the engine,trans is mounted.

Simple, it can handle the power. Your going need to do some machine work to make something work. Your keeping the auto theme, parts are easy to get if needed. The diff. not really any larger that a 90 degree gearbox.

Hope this gives ya some ideas.

I suspect you want to do something like this;

www.bcbosshoss.com

Get posi-traction rear cut one axle off and seal it up. Machine the other axle to what you need to line it up and install a sprocket. Have the drive axle shorten. Have to make a mount on the bike for the rear. To keep it from turning.

ozzb, the diff. either needs to be a locker or a spool. The posi-traction is a limited slip design. With the weight of the bike and how tight it was setup there could be some if not total loss of power to the drive side sprocket. _{my two cents and you basically rephrased my post. Thanks.}

Charles

Well the one i seen done they just drilled a hole through the axle tube and axle and pinned it so it wouldn't move. Cut it off at the pin then crimped the tube closed over the axle and welded it closed. Then welded over the pin to seal that.

ozzb, that works, but I think in the long term the spider gears in the diff would take a beating and fail fairly quickly. There not designed for long term high speed usage.(no bearings on the spider gears shaft.) With the one axle pinned the spiders gears are forced to rotate around there shaft to transmit the drive power to the free axle. I think {been a long time since in a diff} there rotational speed is twice that of the ring an pinion speed when one axle can not rotate.{i may be wrong here}

There there for the slight speed different in the track that makes on an inside wheel versus the slightly faster outside wheel.

I've known a friend 4x4's that had way larger tires and then had to run a small(stock size) tire home from a 4x4 trip. The diff was cooked by the time they got home. About a 100 miles on the spare. The diff was an open style. They upgraded to a locker and bought a full size spare that matched the other four.

This was the reason I suggested a spool/locker. The spool is supported by bearings on both sides. The pinion drives the ring turning the spool then that drives the axle that in it which is supported by the bearing at the end of the axle tube. Simple 90degree change in direction of drive.

The Lincoln locker your simply welding the spider gears to the gear carrier making it into a spool. Some low budget 4x4s do this for strictly offroading. As long as one wheel can slip/skip in turning it works. Usually an axle/drive shaft or u-joint will break. worse case the the ring/pinion and welded diff destroy themselves from the stress offroading.

In this (the OP's) case there should not be any problems due to uneven twisting loads like in my 4x4 examples.