First, you have a great platform for a 3.0 hot rod SC that will be stone reliable and fast. The '78 had bigger head ports that the original that came with your car. Most of your build will depend on the components you already have. If you have Mahle cylinders, you can most likely reuse them with new, higher compression pistons for JE or the like. If you really want to make it work well, consider 10.0:1 CR with twin plug heads. This set up without porting will net around 275 hp at the crank with 46 mm Webers and decent exhaust and GE 60 cams. and lots of fun to drive. I did this for around $7500 with used parts except pistons and twin plug distributor.
