From this thread:
engine choices
I thought I had put part number and link in that thread. But here is amazon link with part num:
Amazon.com: GM Performance Parts 19212593 Oil Pan: Automotive
When I bought from Amazon, it was about $150. The kit shown above is complete and ready to bolt on. Includes pan, dipstick, windage tray, gasket, etc. I wouldn't consider any other pan but the H3 if you can't use the pan you got with your engine.
And here is a pan discussion on another forum:
LS oil pans with dimensions (all of them) - Chevy Nova Forum
It does take a bit of work to get the truck pan to work but it can.