Of all the third gens, the 555 is the best choice, IMHO. Great mileage, no cat and it's an HO with all the improvements that come with it.

You say you don't care if it's SO or HO, but after a while you probably will because that extra power is nice. Towing, or passing, or whatever. And again, the HO has internal improvements over the SO.

I say go with an '04 HO 555. (then install a Walbro). And if you decide on an automatic it will have the 48RE. They are fine trucks with great handling, lots of power and fantastic brakes.

Of course you could go with a 1st gen. Great trucks and absolutely reliable. Tough. Run waste oil for fuel. And they make their own bumps, smooth road or not. But if you look up crude in the dictionary you might find a picture of one. The newer trucks are truly from a later century.

Wetspirit