Personally I wouldn't celebrate a win by forfeit. LOL!
Those 5.0s are formidable opponents and very closely matched with our cars... However, I must admit that I loved the look on the guys face when my LS3 started walkin his 5.0 Mustang.
He was so sure I wouldn't even hang with him, to the point of being VERY kocky and borderline disrespectful, but his smug look quickly turned to shock as I pulled ahead, and he accused me of not being stock. I assured him that I was, (besides a muffler delete) and then asked him to "take it easy on those bowties"!
He was visably upset.
This, on a short PRIVATE, paved surface of course. I made him, humble!