Ok, I've decided that I really want to drive the car and can't hold out for a cheap EFI engine and I really don't want to deal with converting the fuel system at this time. So I'm still going to look for a manual tranny, but want to rebuild my D15A2 ('87 DX). It pretty much just needs the head put back on and I'm done, but while it's off I was wondering about some modifications. I'm trying for MPG and I've been wanting to try Somender's Grooves (SOMENDER-SINGH.com - Home) and with the head off is the best time. Now I was worried how I'd lean out the fuel mixture to take advantage of this since I had a carb and started thinking, I should just deck the head and increase compression ratio. I saw one site that said CR was at 9.2:1 by default, but I can't find info on CC of heads, thickness of HG (and if there are thinner ones available) and how far one can mill before they run into trouble. I realize that these engines are all interference already and don't want to increase my worry, but this engine will spend very little time above 3000 rpms and probably not much above 2000 rpms either. At what point will I have gone too far and have issues with the timing belt being too loose, etc? Should I just shave .050" and see what I get? Thanks for the info.