Advice about a 360.

Use that 360! I have a 1990 360 in my duster that I rebuilt(pretty much the same thing as the 1989 360's). It too has the "308" heads on it.
Just make sure you cap off the smog ports if you are using headers. Use taps and 1/4 inch flat head machine screws. I am also using an A999 transmission (beefier A904 with wide ratio gears) behind it and I love it!