sounds like a lot of miles, the figure your trucks are all 10+ years old, hubbys 99 Z-71 just turned over to 70,000 yes that is a 7 with 0 zeros, and the truck was built in June of 99, (guess he likes his truck) the 89 350 we have, has almost 300k with 2 tranny swaps! it does blow some smoke when you start it but thats it!
1986 K5 4" skyjacker suspension 3 " body, 14 bolt rear, dana 44 front, TIRED ol 305