I believe I have seen mention that the truck pan will not clear car crossmembers and/or steering linkage will hit the pan when turned close to full left or full right.
Moroso, Milodon, Canton, Kevko, and Hamburger are all brands to look into. Check with Impala resto parts suppliers also.
After doing some looking on Ebay just for pictures, it is easy to see where the offending part of the truck pan is, you may want to look just to familiarize yourself with the needed shape.
You can't use a stockpan for the stock 396, it has the wrong shape for the 1-piece rear main seal you block has. You'll have to search for a car style pan for the 1-piece seal block. Oil pump won't need to be changed, but the oil pick-up might depending on the depth of the new pan.
One that looks like it will be what you need is Moroso #20411, fits Gen V/VI(1-piece seal) into '64-72 car, 6 qts, 8" deep. This is a widened sump performance pan, I don't know if you will be able to find a stock sump type pan if that is what you want. You'll have to search.
Last edited by ericnova72; 04-01-2011 at 03:32 AM.