Search ebay for "6VD1" for 3.2L and "6VE1" for 3.5L

You can also put the part name before or after the designations to narrow search.

214 results found for 6vd1
112 results found for 6ve1

Also select "Include title and description" (checkbox) to widen search.

These designations also work on google but I would put "Isuzu" in front of it or you'll have too much to sift thru.