This Ensign was not built in 1978 as no Ensigns were built during that year. However, if you can determine your hull number from the ID on the transom or the metal plate just below the tiller you will be able to use the cross reference in the Ensign Yearbook to find the year of production.
What you show in your photo is unique and was never something Pearson built. Your boat is probably from the time when travelers were not yet legal on an Ensign. I do not recall the exact year that changed but it was late 1960's to early 1970's.
Looking at your photo there appears to be a block near the port combing. There may still be a corresponding block near the starboard combing. The horn cleat in the center was where the mainsheet was cleated. The mainsheet went through a triangular rig from one side of the boat, up through a block on the end of the boom, down to the other side of the boat, back up to the block on the boom, down to the other side of the boat and then to the horn cleat.
You could return to that system - probably changing the horn cleat to a cam cleat of some kind. Or, go to a traveler and mid-boom sheeting (something that was not made legal until several years after travelers).
Hope this helps.
Nick Lubar
Fleet 29 Cleveland
Nick Lubar
Fleet 29