there are alot of guys useing them some will not say that they do...i got a top end kit off a guy that was running the source stuff that was going 5.0s in the 1/8 mile he was useing the stroker kit,timing set,and dist. and didnt have anything bad to say...only reason he sold the stuff was to upgrade to a bigger motor for a diff. class...im going to build a stroker soon and may be useing the kit myself for the money.....i think the biggest thing for most guys is that they say its china made but hey so is the puter they are typing on..jmko mike