I have a old style gearset(thin floor) i want to put in a new style housing that is made for new style (thick floor)gears.Is this possible with a shim change?How much different is the gearset ?

The old style, thin floored gears has a taller bearing inside the gear. The tower in the new case is about 1/8" shorter. In a pinch I put a short steel tower in a case and installed the taller race on it. It saved the case and we were able to reuse the old gear set. The majority of the tower is supporting the load and so far I have not heard of any problems with it. It isnt recommended to do this setup. But it seems to be working so far. This winter we will probably put a new gear set in and make it right. But for a short run to get this drive through the summer, we thought it was worth trying.

With your setup, race shims may be a problem. You will have to run the .090" races and they used to come in .003" steps. They are no longer available from Merc. The upper will have to setup for proper lash and finding shims may be difficult. Not sure if they are available from Sierra or someone else.
Hope that helps.
Dick

I've used S/S shim stock to make shims when I didn't have the needed shims before. Using an old bearing cup with a nice sharp edge ground on the edge and use that as a punch when used witih a peice of hardwood.

Thinking of it, you could use a .030" shim under the .060" race to get close to where you need to be. But if you stack the race shims, they need to be positioned or they might cause a problem..