Yeah, that's a common aftermarket inline unit. You really don't need one like that. They require you to use their replacement parts whereas any inline aftermarket one will work. I used those on my custom applications years ago because they looked cool but they are more money and less filter than many others on the market.
There's only the two different sizes and I would think that all big block engines would get the 800cfm units but you never know. A quick measurement of the primary throttle bore will take the guess work out.