4 link bars

if I am building my own 4 link, what would be a good length for my lower bars? BTW, this is for a 1988 c1500 reg cab short bed.

Are you using the factory leaf spring perch as the hookup point for the lower bar on the frame Blitch? If so just measure from the centre of the bolt hole to the centre line of the axle tube and your set. What will you be doing for the upper bar(s) ? A wishbone that has 2 attachment points on the axle tubes and one at the chassis would probably work good( as long as you have a fuel cell that is).