Hy GMCDumpTruck72, welcome, in order for us to help you we need more information from you about your truck and you need to be more specific with your questions. Larger trucks can be equipped with different components within the same series, there are standard parts and optional ones, for example your truck could come with a 5000 lb. or 7000 lb. front axle. There might be a plate or decal on the inside of the glove box door that will tell you how the truck was equipped when it left the factory, so look for that. Add to that the 70s were a time of change in the braking systems of larger trucks, so we need the most accurate information from you in order to help you find the correct parts for your truck. Keep coming back we'll help you, but you have to help us with the accurate information, good luck.
