Should I buy this Hot 360 Engine

IIRC the 273 rod is lighter than a 360 rod, never heard of a HD273 rod either. Ask if he balanced it.

I'm with Dr dan, I hate to buy "built" engines with out documentation, hearing/driving it or knowing the seller. Personally, I consider them to be worth the sum of their parts.

Mopar Performance offered an HD273 rod through their catalog for years. They were weight matched and came with good rod bolts. Really tough to find these days. That might be what he's talking about.