[Vwdiesel] Better motor?

[Jim Arnott]

Were I to scour the boneyards looking for a 'better' Diesel for my '82
Westy, under what hoods (bonnets) would I expect to find likely
candidates?  Currently, there's a 1.5 bunny motor there, so about
anything would be an improvement.  I'm looking for a NA motor That's
effectively a bolt-in. Am I correct in assuming that the 1.9 was not an
option on American imports?

Thanks.

Jim