Is there a simple/easy way to ID a 273 engine vs 318?

I know they put /6 in C-bodies. I had a Canadian '65 Polara 4-dr with a /6 (and a Fury interior and dash).

A US Monaco / Polara in '67 got 383's standard unless maybe you special ordered a 318. In Canada the standard was a 318 unless you upgraded to 383 or maybe special ordered a /6 (it might have been that some 4-dr Polara's had /6 as standard in Canada, I'd have to read the sales brochures really carefully to verify that).

Our family had a '65 Coronet wagon and I think it had a 273 (I think it was originally a US car). My '67 Monaco (2d HT) that my dad bought new had 318 (poly) but I replaced it in '87 with an LA 318.

While I'm here -

I bought a front sub frame at Moparfest last year (it's in really really really good condition) and it turns out it's probably from a Fury. It's got /6 mounts. That sucks. I understand there's really no adapters for mounting a small block. Best course of action is to cut away the entire K member and replace with my old / original K. But I'd still need to get shorter torsion bars (can't re-use mine).