[Lee H]

Assuming you matched up the throwout bearing with the old one and it matched, I suspect that it was installed incorrectly on the clutch fork or the clutch and or the fly wheel, pressure plate surface was marginal and just can't hold. Afraid your going to have to start over with a new clutch kit. Have the fly wheel turned and pay special attention to the new throw out bearing install directions. It's easy to get those on wrong. Also test fit the pilot bushing to make sure it fits the muncie end shaft.