I've searched around a bit but haven't found a solid answer so i thought i would ask. I took my 87' Ram 50 4x4 on a trip to school about two hours away which was mostly freeway driving at 65mph. I don't really drive at this speed very often but whenever i do the engine is wound up fairly high but i don't know how fast since my truck doesn't have a tach. my question is is what is a safe speed to run one of these trucks at for trips. I think my truck has the 3.909 rear end if i remember correctly. I was thinking about taking this truck on a trip to Montana this summer and all their roads have speed limits of 70-80 mph which im sure 80 is a bit much for these trucks so i wont be going that fast. also if i do go on a trip what are some good spare parts to bring along, i know a fuel filter is a must and ive got a new bosch coil but what other parts are known to randomly fail on these 30+ year old trucks?