I pull my engine before each main and check the clutch. A wise racer told me to do this and it works well to make sure my clutch is up to the duty of a 30 min main. The quick change mount makes this process very very easy. In addition it adds strength that engine mount blocks do not have. This protects the case on your expensive mill from cracking during the abuse that these cars endure around the track. I have been told that when an engine case cracks or breaks a mounting tab usually a one piece mount is not being used. So the quick change mount definatly serves a purpose. I use the king headz one myself but the losi one is good too. BTW the king headz mount will allow you to use a standart 3 shoe clutch system as well.