the best D series sohc came out of the 89-91 civic si (D16a non VTEC) it has steel main caps just like B series. all the others including the D15b have this one piece aluminum crap that flexes under normal conditions (imagine what boost would do)

I actually admire your desire to build your own engine rather than taking the easy way around. I think that in the end you will gain more appreciation and useful experience of the end product than just swapping some used engine into your car and slapping a turbo on it. of course this method isnt all bad.

I currently have 3 completely dissasembled engines (B16a,B18c,B20b) in my garage and just this alone has givien me knowledge that I wouldnt have ever gained reading some forum.

If I were you, Id try to find a better base. sohc or dohc. and its extremely important to buy a HELMS MANUAL for that engine if you dont already own one.