Oops, hit the wrong button there. Can anyone share the secret formula to estimate top speed if the gear ratios are known? I ain't that bright can push buttons on a calculator. Thanks.

Stuff I’m gonna work on, I swear
1963 C30 flatbed
1961 Apache 30 (parts, no title)
1960 GMC Big Bolt

Don't tweet, face, Google, or link. Just hanging in as long as I can...