O.K., then here's what I would do to run the XR288HR cam.....
Bore the block to 0.060" over. Use Keith Black #KB207 hypereutectic pistons and zero deck them. These pistons have a 0.250" pop-up that occupies 25.5 cc's of volume. Use Fel-Pro #1037 head gaskets. This combo will yield a static compression ratio of 10.3:1 and a dynamic compression ratio of 7.926:1 with a piston to head clearance of 0.039". You should easily be able to run low-grade pump fuel.