Hi fastd,
What you're describing is a push, or understeer. What is causing this is relative roll stiffness between the front and rear . . . the front is stiffer than the rear. You didn't mention tire pressure, which should be about 32 front and 28 rear depending on tire size. To move your car toward neutral steer, providing tire pressure is correct, you need to stiffen the rear bar (bigger) or do vice versa to the front bar (smaller). I'm assuming the bar is not adjustable, which would make corrections easier. But first, make sure the mounts are tight before you make this change.
As a side, the bars ERA gave you should work, providing the bars are based on which engine you're using. A big block (FE) puts more weight on the fronts than would a small block, which would cause a push. Of course, aluminum block and heads will juggle the situation. but you have what you have. Make a change and give it a try.
