The Dud donk was in my family and so was the mk II FJ20et, yet the dud motor was a winner in all areas with same turbo and boost albeit some head work, L20b internals etc.
When my father had enough of losing to brother Luis he went for KKK (to4 hybrid equiv) hybrid snail custom mani, mildly ported head with more boost (30-35psi) prepped stock Mk2 rods with forged slugs, made almost 280kw atw & still wasnt that much faster. C16 leaded fuel 550cc inj made over 300kws w/ stock cams.
My R100 BP made 200+kw ate and was 200kg lighter than most datsun 1600s & no offence but would never own an SR powered oldskool 60/70s car just doesnt look right or do way more than some older nissan engines.