They say 5w-20 on the cap and 5w-30 on the hood sticker. So whatever is available to you. I recommend 5w-30 personally. I use 5w-40 in my 5.4L truck mainly because it likes to eat thinner oil.
2000 Mustang GT Steeda #0048 34k miles. 99 Cobra 4V swapped, FTBR IRS swapped, exhaust, tuned by James Gordon.
Just because I give you advice, doesn't mean I know more than you. Its just means I've done more stupid ****.