Leaking Holley 94 carbs

[rhphotord]

Recent (4 mo's ago) rebuilt 94's on my flathead are starting to leak between the base and bowls. Started seeping fuel several weeks ago and further tightening without over tightening doesn't seem to help. Care was taken at rebuild time to not overtighten screws and crush gaskets. Kits were of good quality and advertiised to be compatible with modern fuel. However wondering if the fuel truly does have a detrimetal affect on gasket life? Is a there a superior gasket set? I really don't want a quick fix but a permanent fix. Ideas?
Thank you for the input