Re: 1990 johnson 8hp help!!
Ebay or outboard junkyards like
www.tcoutboard.com. The 6hp cowling also fits, since they are essentially the same powerhead.
You can probably go back a few years into the 80s, too. They changed the design in 1991, I believe. Yours still has the slanted cowling, and I think they were the same for several years.
It's going to be tough to find the 8 hp one. Fewer were sold.