They say I say
 

Quick fuel 650 Q-series carb with billet metering blocks.Bought some standard holley power valve to swap sizes.Had plenty lying around but want new in the package ones.Tried to put one in and it wouldn't screw in,got three of the ones I had tried them in both metering blocks and they wouldn't go,picked up the ones that came out and they went right in,tried the new ones again and it was a nope.Called QFT and they said even though they were "4 window" the standard ones should work.Tried again a little forceful by hand and it will not go and I refuse to risk ruining a metering block over that,the only one that sells QFT locally didn't have the size I needed.

Try the QFT ones that came out of it in an old Holley metering block and see if they fit correctly. Just a thought.It should tell you if the thread is the same or if yours are just goofed up or something.

Everything says both are the same thread.The QFT's I got today from Summit went in by hand though, the others did not.The new ones did not go in as easy as the qft's that came out.They are the 4 window design.

Sounds like a manufacturing issue somewhere.

I agree. That is a manfacturing problem. I would not be afraid to ligthly brush the threads on the new PV's to make the threads less sharp for the intital first turn & see if there is any chance on them going in.

The new QFT's went in.So we'll find out how it does tomorrow night...