more....
Just to amplify a few things that George said.
The elevator and rudder skins are .016. They have a tendency to crack. Seems to be more pronounced on the high HP airplanes. I rebuilt my elevators with .020 skins as I thought this would be needed eventually. I then went out and bought a 160hp wood prop -4 with .016 skins that has had no cracks in almost 900 hrs (go figure).
The engine mounts in the early airplanes had a tendency to crack. There's a series of angles inside the fuse where the engine bolts through the mount and the angle ties the mount into the fuselage longerons. Van's came out with a change to the angle (thicker). Definately worth a look. Cracked mounts are often thought to be an inidcation that the owner is landing hard. This may or may not be true. I'm not convinced one way or the other.
Slosh. A new set of tanks is about $1700 from Evan Johnson. The slosh was a gooey coating that can peel off and plug fuel lines etc. If you look in the tanks and see aluminum, you're good. If not, you need to investigate further. Sloshed tanks were a buy/walk away item for me. Also, be aware that there were at least 3 different materials used over the years to slosh. Only the gooey one is harmful.
Most of the early airplanes had no air filter of any kind. This was common at the time but somewhat shocking if you have no experience with it. The FAB airbox kit is about $200 from Van's but requires some FG work. Carb heat is generally just a flipper which allows the engine to breath engine compartment air. Early airplanes also do not typically have a full swivel tailwheel (another $200).
How does it fly ? Will it fly hands off in calm air. Will a 160hp airplane do 150-160kts + ? Will it do it on 8gph or less ? If not, something's up. How much does it weigh empty ? Heavy airplanes can feel substantially different from light ones.
Lastly, you should think about maintainability and resale value. A hyper-translucent multi color flame job might look cool now, but how are you going to feel about it in a year ? How will a potential buyer feel about it ? Similarly, a super hyped up engine might seem cool now, but who's going to work on it ? Will you be able to sell it after a potential buyer has it inspected ?
As George pointed out, the value of these airplanes is great right now. As the market shifts towards the latest/greatest and most powerful, a nice 4 can be had for 1/2 the price of a typcial RV-8. But hey, let's keep that to ourselves
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Good luck.
John