Dean, my guess is that you won't damage anything. Here at my place, we have run E85 in couple of cars that weren't converted in any way. Just poured it in and drove. The first was a '90 thunderbird with a 3.8 V6. The car started and drove just fine, like it never knew the differance. Didn't even throw a 'check engine' code. But we tried this in a car that was already all paid off years ago, and it had 189K on the clock. I wouldn't experiment on something under warranty, or something that I couldn't live without if it failed. Next I ran it in a '91 Buick Regal, with 234K on the clock. It also started and ran and drove just fine. The Buick's check engine light was glowing, but that was way back before 200K, so we can't blame that on ethanol. Several guys are running E85 in Chrysler minivans that are not supposed to have it, with no problems. Your OBD1 truck will try and compensate if you run ethanol thrrough it. The computer will sense the differance in the exhaust and tell the injectors to squirt more fuel. They can do that just fine. But they can only squirt a certain amount, once they are at 100% of their duty cycle, there is no more to be had. So if you are running at more than 3/4 throttle, there is a risk of running lean. Running lean can hurt things. So if you want to do this, you'll either have to discipline yourself to not flatfoot it, or you'll have to increase the fuels systems delivery capability. You can do that by switching to larger fuel injectors or raising the pressure on the ones you have. If you don't know how to change the pressure, find someone who does. Nevermind the fact that Ford, GM, and Chrysler and their dealers tell you you can't do this. You can. You must keep in mind they don't want you to because they are in bussiness to sell you NEW stuff, not help you with your old stuff. Keep in mind that most of the bad things you hear about ethanol are either misunderstandings or just plain lies. It is very usable stuff, but you have to think it out first. If you want 'pour it in and go' you want butanol. But I don't think anyone is selling that commercially yet. DinosaurFan, on work's old cast off 'puter