first of all if you're going to successfully build a sohc...take out the weak spots:
weak spot #1-headgasket. something about those fuckers just sucks. get a copper or metal multilayer headgasket. #2 connecting rods #3 hydraullic lifters. If you take care of all that shit, you can turbo it with no problem and put down 300whp fairly reliably on a daily driver. I have a fully built race head for SOHC's for sale, high performance cam, nismo cam gear, 5-angle valve grind, solid lifters (adjustable),PM me if you really want to do this.
My fav site for SOHC goodies: www.NIZZX.Com