I am planning on building a "T" antenna tuner

I scrounged up an old 5KW RF deck (FREE!!!)
It has 2 large caps (1 is much larger and has 2 ganged section) and a 10
turn tapped inductor (air core).

Would I use the larger cap at the antenna side of the inductor or the
receiver side?

Hi Pat, With all the T type tuners I have played with, one cap is always set
to maximum. Which one depends on whether the complex impedance you are
attempting to match is inductive or capacitive. I would think the larger cap
would be preferred on the one set to maximum, since that cap needs to be a low
impedance to rf.
To make your tuner more versitle, use jumpers or switches or whatever to
exchange the positions of the two caps. That way you have the best cap in the
right position for the impedance you are attempting to match.
W9CF has a neat T tuner simulator on his web page. I found it to be very
educational on how these tuners work, and helpful determining the value of the
components I needed to match various loads.
73 Gary N4AST