Is there a physical difference in size in these engines, and what is it?
how easily do you think a L16 with a stumpy five speed could be fitted in a 1000 sedan? L18 ? L20 would be too big... to fit easily.

basically i am looking for a cheap midpoint between a Ca18DET and an A14 (already have)???
would it be worth using a Ca18 / 16 DE
any ideas as to approx cost?
any suggestions / comments much appreciated
-Cal

The L16 and L18 are the same external size. The L20B is taller but the same width and length. The L20 is a straight six cylinder.

L20B block is about 20mm taller than L16/18 blocks. Wether or not you can get it (or any of them) under the bonnet, I don't know. You'll have to do some measuring.

L20A is the six cylinder 2litre, but was not released in any Australian Datsun/Nissan and is quite rare, so that's why we don't bother calling the 4cyl L20B, just L20.

Anyway, the biggest problem you'll have with any swap in the 1000 is the trans tunnel - they are tiny! Expect to have to modify or replace the tunnel with any engine swap.

Another 1000 specific problem is the transverse leaf which runs through the enine crossmember. So you can't modify the crossmember if you need extra clearance - you'll have to modify the sump/oil pickup if extra clearance is required. Not a big problem.

Stanza and 200B sumps and pickups would be the best starting points as they are most similar to the A series sumps with the pickup & reservoir at the front