I bought the base level crate years ago and it while it isn't great for gobs of power, it ran great and I could still break land speed records with it. If you get the base crate and don't care about the warranty, swap in a torquey cam before the first start-up and enjoy a more powerful engine.
I've installed 3 of the base Goodwrench 350 crate engines over the years -- one in my 69 C10, the others in friends' 51 Chevy truck and 55 Chevy car. All had small 4 bbl carbs (450-600 CFM) and headers. By hot rod standards it has crappy heads, low compression, and small cam;
however, everyone was happy with the power, even surprised by it! Smooth idle, zero valve train noise, torque right off idle, and that old school mellow sound through glass packs or modern performance mufflers.
The one in my truck got a Summit K1102 204/214 cam, which gained me 500 RPM and maybe another 20 hp, with a slight loss of torque down down low. Next time I would choose a different aftermarket cam with an earlier intake valve closing angle to keep cylinder pressure as high as possible -- like a Summit K00032, which looks identical to a Crane 100032, probably even made by them for Summit.
But compared to a stock 70s-80s engine, this engine with a stock cam rocks for everyday use where you want to good power from 1200-4500 RPM.
Another Plus: Standard heads and manifold with heat riser passages to warm up the carb. Vortec heads suck in cold weather unless you have EFI.