Jim,
If you move up the merger/food chain you'll find that Weedeater is now owned by the Electrolux corporation, along with a whole slew of other acquisitions. I think Poulan is in that group as well.

I've got one of those engines, too, I think. Bought a Weedeater leaf blower on the sale table at WallyWorld. First thing I discovered was that the thing weighed a lot more that my Ryobi's or Homie's! The cylinder and block is physically larger, too, as well as being double-ringed. The carb is a WT-538. My rear carb plate was black plastic, though; so it may not be the same model as yours. The shape of the cylinder top sure looks the same, tho...

Kiv