If you're replacing a top-end on a 250/300, the Vertex replacement kits do not include the wrist pin bearing - not sure about Woosner? Seems whacked to me that a top-end kit does not include this bearing?
The bearing measures 18 x 22 x 22mm - caged needle bearing.
You can buy them here for cheap:
http://www.mfgsupply.com/09-505.html
North Tahoe Motorsports does it right and sells you everything you need in their kit:
http://www.ebay.ca/itm/TOP-END-WOSSN...item53fcbb21fe
Dealt with both vendors before, and both are first-rate.
Jason