72 commander 31 sedan question

Good evening , on my 31 sedan , my dad and I took it out on the lake yesterday. We were running half throttle ( throttles we’re straight up ) tachs said 4K rpm , and I know that’s not correct. My question , to get these boats to plane , do you really have to pour the wood to them at 3/4 throttle or more to make them break over and plane ? Props are correct factory size and new , and bottom job is also fresh . This is a sedan with twin 350q engines and original heavy kohler Gen set . So it is rear heavy.

Thanks guys.