Yr-4 / Yz10 slipper retrofit. Some help please?

[AllenB.5979]

I have an early Yr-4 that I have done a custom conversion on basically turning it into a Yz10 without the Yz10 if that makes sense. It has the motor mount / center bulkhead from a Yr-4 and currently has a spur and rear drive pulley combo from I believe an 870c with a one way bearing set up. This is supported by a Yr-4 center shaft and a Yr-4 front drive pulley. The front drive pulley is M3 pitch and the rear drive pulley / spur is an M2 pitch. I would like to keep the belts the way they are (M3 f and M2 r) but I would like to put some type of slipper set up on it. I don't have an extensive parts bin for these cars to play with and just guessing and ordering can get expensive. Does anyone know of a set up that might work for this application?
I think the early 870c was all M2 pitch so maybe something from that model? I don't know if they made a slipper for that car. I've also seen different center shafts for different years and models so I'm not sure what will work with my bulkhead. Any help from someone who has a grasp on the different parts from all of these cars would be greatly appreciated. Normally I would just keep trying until I find something but I would like to get it right the first time with this one. Thanks!

Here's a link to the build so you can see what I'm working with.

http://www.rc10talk.com/viewtopic.php?f=29&t=41329

[rccars4sal]

The slipper clutch assembly for later yz10 will go right into the standard center motor mount bulk head. They are a bit hard to find, and lately, might as well be gold plated. Folks are getting top dollar for completed units. that being said, theres an mx4 slipper assembly on ebay for less $$, but I still think too high....The mx4 setup will go onto a standard non slipper 870c layshaft, but the end of the shaft needs to be threaded so the slipper assembly can be tightened down for minimum endplay. You could also use the layshaft as is, but it would need precision shimmed to make the mx4 slipper clutch secure.

[AllenB.5979]

The slipper clutch assembly for later yz10 will go right into the standard center motor mount bulk head. They are a bit hard to find, and lately, might as well be gold plated. Folks are getting top dollar for completed units. that being said, theres an mx4 slipper assembly on ebay for less $$, but I still think too high....The mx4 setup will go onto a standard non slipper 870c layshaft, but the end of the shaft needs to be threaded so the slipper assembly can be tightened down for minimum endplay. You could also use the layshaft as is, but it would need precision shimmed to make the mx4 slipper clutch secure.

Great advise. Thank you sir! Yeah they definitely are pricy but what can ya do. Especially if you want to run brushless without destroying the drivetrain. I'll have to scrape my pennies together and see what I can do. the