If it has the same pistons as stock, '78s should be flats I beleive. Mine is a '75 with dished pistons, so I'm keeping my N42 head so my comp doesnt drop to a measly 7.x:1
If you turbocharged the motor in your '78, you should have no problems running stock boost on stock electronics, and no problem boosting atleast 12 with an intercooler.
Oh, and it took 3-4 months of waiting and inquiring about every possible turbo parts car to find the deal I did.