You are not going to find very many Olds guys that have, or are willing to, put a Buick motor in an Oldsmobile. Most of the time they will use an Olds 455 because it will bolt right up in place of a small block Olds, a Buick will not because the mounts are different. If you do not have any luck here, try
www.v8buick.com . This site may have some Buick guys that have done this or know how to do it, hope this helps.