I have a pair of 1984 454 330's, I'm trying to find out which heads I have without pulling the valve covers. I've been told early engines had oval port heads. Does anybody know if this is true and what year they changed the heads for sure?

You have Oval Port Heads.

But there are a couple Oval port heads and you will never know without a number.

Ok, so they changed to round (peanut) port after 1984?

I'm thinking mid 1970's is more like it. They started using them because of emissions requirements.

049 and 88 are kind of the factory "good" oval/round port heads.

Probably the 049's or at least similar casting. Actually excellent marine head. I have 4 of them on the shelf that came out of a 78 boat.

I have a set sitting on a shelf myself. Came with one on the core motors I used to build and just couldn't rid of them.

781 and 049 are the oval/round ports. 088 and 188 are rect port

In '84 they were most definitely the round or as most motorheads refer to them as peanut heads. The 088's were rectangle. They were used on every 454 over the 330's. 370,400,420 and up.