I believe an NA 4.3 of that time yielded 160hp. The L35 has different heads, cam, rods, intake, block, fueling system...everything. The Syty engine is same as the regular 4.3 of that year, other than the pistons, main caps, intake.
If you took a Syty motor and put it to being naturally aspirated, you wouldn't make that 160hp though. They switched to lower compression pisons in the Syty, so it'd make less than 160 actually.