I have a 70 K5 with SM456 & NP205. I am pulling out that combo (and its for sale with everything including a new clutch with 8 miles) and have a 88 K5 and 71 K5 donor truck. I have a bunch of questions... My 70 K5 has 4 wheel manual drums. I have a 71 or 72 doner that has the discs on the front and power booster. Now I have an 88 K5 with power discs. What do I do??? I think I have three options: 1. Can I use the rears from the 88? 2. Swap rears from 71 parts truck with front disc brakes but I dont know what condition the rears are in (very rusted and would need complete rebuild of brakes anyway) 3. Use my drum rears that i know are ok and swap the disc brake parts from the 71 to the 70? (knuckles and other parts) Can I use the power brake booster setup from the 88 on my 70 with the mounting bracket form the 71?