What's your elevation? I am at 3000ft and stock tires. If you are close, i can give you my setup. it is pretty darn close to perfect….Mine did the same thing, yanked them both off and replaced with qsc primary and stm secondary. No slipping now. I just have to dial it in. I bought it used and its nowhere close. I strongly suggest ditching the stock clutches. Just for the peace of mind and the extra performance is nice too. I can lay a blackmark about 10 ft. long from a dead stop and im only hitting 7400 rpm right now. Need to see 7800 rpm.