If your Holley carb has clear sight plugs, think about replacing them with brass. The first two clear plugs I had I twisted off the heads trying to tighten them when hot. I had to disassemble the carb to fish out the remains of the plugs. I replaced them and though I was golden but just found the back one has been leaking for some time and won't seal. Just ordered some brass plugs.

Clear sight plugs are for adjusting fuel level only.

Now you tell me. My carb just came with the clears so I think Holley intended them to be permanent.

I had a set of the clear sight plugs that worked great for around ten years. One broke or twisted off do I bought new ones thinking that they would last at least for a couple of years. They both broke off within the first month when I went to make adjustments.

Yeah, they get soft when hot. I tried tightening one with the engine hot and the head came right off.

The problem I had with the clear plugs is that I could never actually see the fuel level. I always ended up removing the plugs to set the float, so I just put some old brass ones in (this was a Holley HP carb). The clear plugs were a good idea, just poor execution.