Does the '84 have a seperate intake, or is it part of the head?
Not sure the older covers fit the intregal head.

Try ( www.Inliners.org ) and check there links and swapmeet area.

Mercruizer is about the only real stock replacement aluminum cover out there. I have see some aftermarket race type covers, but they are real expensive. Checl your local boat repair shop, you may get luckly.

Joe