tips on upper intake removal, 88f150, 5.0

[racer_inboston]

I have a used motor that needs the valve cover gaskets done so I need to remove the upper intake plenum. I know that there is a stubborn bold in the middle, anyone know what size or tool is best to remove this?
Thanks

 

[racer_inboston]

i'M ALLSET, EASY JOB, BEEN 10 YRS SINCE i LAST DID UN UPPER.