Compression with a 58cc chamber cylinder head and a 0 deck motor is 9.8:1
Probe was one of the only manufactures offering dual relief pistons but in recent years they have split them to 2 separate lines, TFS and INLINE only, unless someone has some older inventory. What piston did you buy?
If you are going to stick stock heads and intake on the motor, Id go stock cam as well and save till you can afford to do heads otherwise your wasting money. If you cam it for what a large head and intake could use it will hurt the power and torque down low and the curve will be lazy IMO. ID run stock injectors and MAF as well till you upgrade the top half on the motor. Like mentioned, cam would be the last thing I design....
If you were my customer and wanted inline style heads, Id go 58ccAFR185, Holley Systemax intake, 75mm TB, 80-95mm MAF and 30lb inj, TWISTED wedge FAC 190cc milled to 58cc, RPM II or TFS Track Heat intake, 75mm TB, 80-95mm MAF, 30lb inj
My $.02