I am currently in the middle of the L18 into a 120Y conversion at the moment and the L18 has a worked head and twin SU's, and so far the converison has cost me about $400 dollars and that includes a complete 180B sedan which was licenced and a set of stanza struts with 200B discs and i got the calipers later. i have a TRX 5spd behind it and i might even be able to use the 180B tailshaft but i'm not sure yet. must look into it. but wil let you know.

for $4500 you can have a nice slightly worked street rebuilt L18 with 5spd and twin carbs and everything else done including a decent interior for that kinda dough as long as you put in the effort. just be on the lookout for good deals.