if i am using aftermarket rails and my cross-over is at the back of the intake, would my leaner cylinders be the ones at the end of passenger side rail?

 

In my experience, the location of the cross-over should not affect the fuel distribution all that much if your pump is doing it's job. On LT1 cars that have aftermarket fuel delivery systems and more-than-adequate volumes/pressures, the lean cylinders are the ones closest to the throttle body and the farther back in the plenum the air has to travel, the richer the mixture that gets to the cylinders. I've hypothesized that the front cylinders take more than their share of air. This phenomenon is the same with stock manifolds or with my Hogan sheet metal unit. I would suspect that a single-plane conversion is about the only way to resolve this issue.