I might be wrong but I think this only true if you upgrade the Core Duo to a C2D. Lion is now 64 bit only. It can run on a 32bit kernel and EFI but since Finder is 64 bit you are going to struggle with a 32 bit Core Duo cpu. DP1 ran in both 32 bit and 64 bit mode but Apple took out 32 bit support in subsequent releases.