Leveling '69 K10

[KyFarm]

I have a '69 K10 with what I believe to be stock suspension. It has new shocks but original springs and now has a heavy ass 402 in it.

It leans pretty far forward for my tastes and I would like to level it by raising the front end. The rear has a 1" plate but I believe that to be stock and I don't want to drop the rear any, just raise the front.

here is how I measured it and what I found.

floor to bottom of front and rear marker lights, rear is 3 1/4" higher
There is only 1" more space in the wheel wells though, rear is higher
The top edge of the bed drops 1 7/16" over 4'

Here is my main question...

Where do you measure to figure out how much from lift you need?

and is this just a common problem solved with a 2" lift kit?

Thanks for any help