8.1 liter injectors into 5.3 liter

[aarolar]

is there any gain from injectors alone?

I don't think so not unless you have pretty extensive mods like some sort of FI. The computer will only dump as much fuel as you need irregardless of injectors.

[Weirdguy]

I don't think so not unless you have pretty extensive mods like some sort of FI. The computer will only dump as much fuel as you need regardless of injectors.

Fixed that for you