a good one is a hydroboost/master setup from a M series (Astro/Safari) van. 1" bore MC if I remember correctly. Hydroboost just ROCKs also, way better than 4 wheel steering. You might need it with the rockwells. The proffitts cruisers guys all run rockwells with toy driveline disks that stop very well. Might be worth a shot IMO if your braking is not very good.