Thousands (two or three I'd guess)
Some things to consider:
Staying carb or going EFI?
Roots-type or centrifugal supercharger?
Do you want to intercool or not? If so, you better go EFI!
Better change your exhaust to accomodate more HP
Same for fuel system
Supercharging 1200cc might get you 110-120HP (almost 100% increase), but for that price you can convert to an L20B and have that same HP w/out a supercharger
and the hassles involved.
Dave Lum
'72 1200 getting SR20DET
'71 1600
'00 Maxima SE
www.datsuns.com