rear suspension? 4 link? caltrac mono leaf? street lynx?

What’s the goal for the car? And what tire will you have on the back? Caltracs and monoleafs can work well and there are guys going 5s on em with a drag radial. More street than race, I would go that route. More race than street and a slick I would look at a multi link and coil over set up. Either way spend the money on adjustable shocks.