Anyone know where I can find a longer version of the 6" long, curved oil filler tube that is standard on 6.0L GM SUVs. I'm making a custom engine cover that will extend over the valve covers. The dipstick is long enough to let me cut a whole in the new cover for access to it. But the oil filler tube is about 2" too short. I see extension tubes for sale on Amazon and Ebay, but it's unclear if they attach to the existing tube or replace it. If it attaches I can cut it to length and make it work. But if it replaces the existing tube it won't work. Anyone?