Bottom line, they fail. The T5 was designed for use behind 6 and 4 cylinder engines, not V8's. The stock or mildly built 302 is one thing, a 351W makes much more torque, causing that much more strain on the weak link. I've shattered T5's without the aid of slicks or even being on a race track. They suck and I'll never use one in any of my built cars again, provided that car weighs more than 2600 lb. or isn't built for serious power, or both.