If it's a 74 it is going to be a little different than the 78-79 models. It more than likely will have a 360 or 390 FE style motor. Good motor but it will suck gas horribly, Not that a 351M-400 won't but they are getting rare compared to the 351M-400M motors. Unless someone has swapped one out.
Also the frames are a bit different than the later ones. They have a stack of springs for sure but they a re narrower than the later ones. I used to have some High boys and they were tanks. I think you would be happy with that truck as a firewood truck. Look over the frame for rust trough and take a good look at the spring packs for broken springs.
Also another thing to look for is drum brakes on the steering axle, not so diserable. The bodies are pretty much the same except some trim and front grilles. You can tell the year of the truck by the front grille easily if you pay attention and know what they are.
The rear axle will probably be a Dana 60, maybe 70. Great axles been around for ever, 4:10's are very likely, you should be able to look at teh diff. cover and if they still have the tag bolted on it will have the gear ratio's marked on it. Post some pics if you buy it!!