Your foam target is not a critter. Your comparison of penetration is completely flawed.
With field points or broadhead, it doesn't matter. Comparing penetration on foam is a non-valid comparison as different law of physics apply between foam (solid) and visco-elastic fluids (critters) . The same wrong comparison will give you the impression that a faster and lighter arrow will outpenetrate the slower and heavier arrow using the same broadhead.
What bow are you shooting now?
I would feel confident to hunt a bear with my 50# Wing recurve and an aluminum or wood arrow of around 480 grains, even though I only draw around 25". And I bet I get around 160fps out of that combo. Normally I use heavier bows, but that doesn't mean it is not an adequate combo.
Compare kinetic momentums and not kinetic energy and your combo will look quite good.
A lot of people think that traditional bows are not able to kill things, until they see the proof themselves.