First off, Welcome to RME!
Toyotas are known for reliability... not power. I'd be a bit leary about the V8 conversion, it's probably nice on the wallet with that propane option, but I believe you loose 10% power and mileage with propane. You'll have to figure that into the cost savings. The engine, overdrive, propane, etc are all very well thought out and expensive options. Someone really put some thought and effort into that build.
What are your intentions for the Landcrusier? That looks like a really good daily driver / exploration / camping rig. I wouldn't take it 'rockcrawling' as it's quite clean. With a Quarter Million miles on it, things like axle bearings, seals, u-joints, etc are going to be failing often. We have a '92 FJ80 that recently turned over 200k and it works well, but you can tell it's getting tired.
So, for $8k, it's alright.... I don't know that I'd buy it. I think you could find a decently built FZJ80 that's more cushy, more capable and all Toyota for better reliability for about the same price.