I have a 88 Iroc with a 10 bolt and drum brakes and i'm swapping in a 9bolt with disc brakes from another 88 Iroc. I know the rear ends will swap no problem but I have a few questions about the brakes. From searching I guess I need a new prop. valve and master cylinder. I know the prop. valve is a must, but do I really need a new master cylinder? Also the 9bolt does not have the PBR aluminum calipers, is this a problem or a big deal? any help would be great. thanks Jay