the very early boats had 110 hp 4 cyl volvo and 165 hp 8 cyl interceptors with eaton drives. the drives were weak and then they put the eaton name on the volvo aq200 which could take more power . then Holman moody got involved . the late 60's saw a boom in muscle motors and that trickled down into the marine world. HM started to put the 289 hi po motor in boats at 271 hp, then the 302 235 hpand then the 351w 290 hp. the owners back then were no different from todays owners bigger is better. My 67 16 was repowered 2 years down the road in 69 from a 210 hp 289 and aq 200 to a 290 hp 351 and aq 250. When i say early boats i mean 64-65 ish. My 67 took a good beating with me and the new owner has shown it no mercy even running it up on the dock and the hull has not failed. in the early 70's they were powered by sbc lt1 motors up to 350 hp. a 16 with 300 + hp is a fun boat that everyonce in a while will jump up and scare you, but for a 16 foot boat handles snotty water really well once you're used to how it handles. My 16 never failed to get me and my family home even in 5 foot wakes on a busy day in 1000 islands.
good luck on the search ratickle has listed a few candidates