sleeves wont fit into block in my B

I bought a used set of m&w sleeves and pistons for my B and i have a set of agco orings.i put the orings on the sleeves and they dont fit past the top hole in the block.if i take the orings off the sleeves they fit into the block.but seem snug at the bottum.looks to me that the oring groove is not very deep into the sleeve.maybe there is a different oring for these sleeves. any information would be very helpful thanks.

Yep, just like on the other engines M&W uses a smaller diameter o-ring.

Measure your grove and diameter, measure the block bottom counterbore. You will be able to get o-rings from McMaster Carr. Buy Buna o-rings there and you'll likely get 25 or 50 of them, but they're cheap. I've went through this and sometimes I've turned the o-ring groves on the sleve to accept a different o-ring. It seams you can alwayse buy o-rings smaller than you think you need and they're still to big. The sleves have to take pretty good force to drive in or they won't seal.

I like the smaller o-ring that the M&W sleves use, it leaves more sleve material. But I don't like the square grove they cut with a sharp corner.

You said the sleeves were snug without O rings. That in its self is wrong. (ANY) wet sleeved engine needs to have the sleeves to be able to rotate 360 degrees by hand. They are not to be snug without O rings.