I'm ordering an engine for my 06 XC90 and I found one from an 03 S60 I believe. I've already done one engine swap and removal on this and from the pics it looks identical. My concern is this message from the seller:
"Yes indeed, this one looks like it should be a fit for you! Do you know your Engine ID by any chance? That will be the determining factor; my fitment information says this will work for engines up to ID 2816209"
My original block number is 3813285. I can't find anywhere that addresses this statement at all other than a third-hand comment in a forum about transfer case clearances for AWD.
Any insights?

 

there should be a sticker on the timing belt cover with both the B code and the serial number. If not, its stamped in the block on the firewall side of #1. You can read up on your engine by googling "Volvo Modular Engine WIKI" which will show what years/models ran each engine variant. Finally if you want to search for used engines, try car-part.com for a listing of recycle yard inventory nationally.