I have a miss and cant figure out what is causing it.I have a 360 and take off is good and idle is good but when you get up to speed you can feel the car jerking forward.When I nail it,and get in 2nd gear around 5500 rpm it will sputter and pop through the exhaust. The motor will turn up around 6200 rpm.I have replaced the wires,spark plugs,installed a summit racing capacitive dischareg box, MSD Blaster coil, and mopar performance distributor, and the miss wont go away. I have adjusted the timing and everything on this motor is new,I just dont know what to do next,where is the miss coming from?  

How long have you had this problem? Is the fuel you are using a good enough quality or high enough octane?
Have you checked the carb? Could need adjusting. Have you changed the fuel filter and or checked the fuel pump?  

It has been doing it for about a month. I mix Cam 2 with 93 Octane 50/50. Im running Keith Black Pistons 10:5 to 1 Compression. I have a new Holley 750 with vacuum secondaries and it seems to be flowing OK and the car Idles fine.Replaced the fuel line with new one and new filter. Im using a stock mechanical fuel pump. Is it possible that the stock pump is not feeding enough fuel to the Carb?  

If you have a real 10.5 comp sb you probably wanna run around 30*-34*total timing maybe less like 28*or so. If you want you can set it @ 26* and go up from there till the power goes away. As for the fuel pump, well I run a stock fuel pump with no problems w/340 10.5 xhead 284* .528 so I think your fine unless it's failing.
And are you sure your secondaries are opening?  

Sounds like a lean miss, I would triple check the secondary's to make sure they are opening. If you have another carb a quick swap would rule out any problems in this area.
MSD recommends going up in jet sizes if you have a high speed miss, I had a similar problem went up two jet sizes in my Holley and the problem was solved. Why? Hotter spark can cause a lean condition at high rpms. Also check the coil for any oil leaking from the tower or a hair line crack in the tower area of the coil.