[EFI70Blazer]

Since both my Blazer and my 86 short box are apart i can't really say which upgrade was best. I did upgrade to 3/4 running gear in my 86 before i took it apart. Went through 5 half ton rear ends before that, so it was probably my best upgrade so far. All my failures were ring and pinion gears, 4 were from junkyards and would only last 6 months or so. The last one i replaced the ring and pinion with a new one, but it still only lasted a couple of years. I will probably have to upgrade the front to a Dana 60, but don't have the money or time right now.