I've always used Fel Pro 9333 head gaskets for 5.0 builds/HCIs. Perfect every time. And if you are busting down to pull one head off, you might as well do them both IMO and add ARP studs while you are in there.
Hell, now would be a perfect time to upgrade to better heads/intake. Most ppl this happens to use it as an excuse to upgrade lol.
2000 Mustang GT Steeda build #48. Bolt ons, suspension, Novi 2000.
Just because I give you advice, doesn't mean I know more than you. Its just means I've done more stupid ****.