Power brake booster size - Help

Here is a kit with master cylinder and booster. It's 8" in diameter.
1965 Plymouth Barracuda Booster Master Conversion Kit

Hi Rusty thanks for the link.
Curious if anyone has used a power brake booster package from Master Power Brakes and what their opinions are on it?

I am close to having all parts for my barracuda disc brake swap, I just finished a conversation with a guy that has a power brake booster bracket (not sure of the year), I was thinking I could buy a power booster for it. Rockauto has one for a 1973 duster. What's the difference between 73 and up vs 72 and older. Just the diameter? will a 1973 fit in a 68 a-body with a small block? is the brake booster bracket different? With that said these booster packages from MPB looks too be great!