He would need a Chevrolet bell housing, though. One that matches the crossmember mounts and correct starter mounting style/location.
Starter position dosent matter. All LS starters bolt to block not bellhousing. You are correct he would just use a older truck style open bottom bellhousing. I have never needed one with the crossmember mounts even though I have one in my truck. I added a rear crossmember to the tail of the trans.
