Holley bowl screw stripped

[6768chevylover]

I had my vehicle serviced at a local garage by me and they told me they had to replace the power valve. After a week of having it I noticed a gas smell coming from the engine bay. I popped the hood and noticed gas on the front right corner of my holley carb where the bowl screw is. I tried tightening it but it just kept spinning.. I tried seal tape but it didn't work.. Anyone have any other ideas to try? The carb is a Holley 700cfm double pumper..