79-80 Model years are N42 blocks, 81-83 are F54 blocks, both N/A and turbo. The turbo F54 blocks had the same 10cc dished pistons as the N42 N/A pistons, but the ringlands are thicker.
The N/A F54s have flat top pistons, but it only bumped the SCR to 8.5:1 stock vs. the 8.3:1 from the N42. I have a 1mm HG [stock is 1.5mm] on my motor, and according to LEngine.exe it is at 8.7:1 now.
Check out this Nissan overview with actual numbers:
http://forums.hybridz.org/showthread.php?t=153226
I'm using the flat top pistons, everything is going great so far. The N42 should be fine with boost and proper engine management. Here are the details:
http://forums.hybridz.org/showthread.php?t=153195