The action is on the turn, hero's equity is 40% vs villains 60%

hands are turned face up now just for this example

hero needs 34% equity and has 40%

my question is if we jam and gii here is this always a plus +EV play even though we are behind 40% vs 60% in equity?

It seems yes as pots odds say its a +EV play but just seems weird because we are behind in equity when gii.

When there's lots of dead money 'padding' in the pot, it can be profitable for both players to get all in, in order to realize their equity (share of the pot).
I think it's easier to understand if you look at a river spot where you're considering calling with what is often the worst hand. You should be fairly frequently calling pot-sized bets even when you expect to lose most of the time. After all, versus a pot-sized bet, if you win a third of the time you break even, so you'd actually be making a mistake if you folded the river if you had >33.3% equity. If you only ever put money in the pot as a favourite, you probably wouldn't make money. You should want to put money in the pot if - on average - you get back more than that amount in the long run. Your bet or call is the risk, and the portion of the pot you capture is the reward. If the risk is less than the reward, it's a profitable bet.

thank you

I have years playing poker, best response I have read on the subject, thanks