Can I use 67 273 heads on my 69 318?

FWIW
I am running the factory solids on my smogger-teen factory hydraulic cam, no problems. I put 5 or 6 winters on that set-up so probably 25000 miles at least. Then sold the engine to my son who drove it about another 6 years.
I too can be cheap,lol. I had the stuff so nothing to lose.