Looks like an old possible english lugged frame with a truss tube crudely brazed in and rear drops changed.
Messaged seller and let him know its not an Iver 2 days ago.
Looks a bit like a freewheel or modern BB pattern
You could make a tool with a piece of pipe and a grinding disc
Recommend you put a ton of penetrating oil and some heat into it before you put a spanner to it
Not everyone in Houston would have turned it into a bar hopper. There are a few cabers around town. Bars are all closed now anyway.
Seriously thought, great looking frame.
Was it a CL score?
What’s your component plan?
What’s the threading French? Italian? Swiss?