My Stepson has a 406 small block running alcohol in a 69 Camaro.  This past weekend at the track we did run 5 consistant passes at 10.70 126mph with a 1.52 60 ft time. However no matter what we did the the #2 cylinder would not fire.  We replaced plugs, wires, cap and rotor, checked valve lash, did a compression check.  Every on around us at the track was helpful but to no avail we are still pulling our hair out.  Any ideas are welcome.  

Have you tried a leakdown test at TDC and BDC??  

have not tried the leak down but will give it ago.  thanx  

Sounds like a compression problem if you checked everything else correctly.  

Try this: Pull all the wires off the distributor and let the boots sit on top of their respective towers. This will force the coil to deeply saturate the secondary side. If a plug is fouled, it will clear out immediately.  

i would think that putting a timing light pickup on the coil wire and firing up the motor while looking at the flashing bulb... you will be able to see if the ignition system is putting out an even amount of sparks...

then move the pickup around to various wires to see what they look like... then test the #2 lead...

what i am thinking is on some dizzys... the reluctor only passes one blade at a time past the pick up coil.... if that reluctor arm has a crack  it will not cause a pulse in the pickup coil with enough voltage to trigger the module on just that single cylinder....

small diameter gm hei dizzys have a reluctor with a ceramic magnet that is riveted into a sandwich on the shaft... when that magnet cracks... it causes random pulses to the module and really can do some strange things to the drivability...

reluctors retain a small amount of magnetism... when the shaft rotates they pass a small magnetic field past the pickup coil...  if you use a digital volt meter set to 2K ohms (2,000 ohms)  the pick up coil should read 600 to 1500 ohms...   if you get a reading in that area... change the switch over to AC volts... when you spin the dizzy shaft you should see over 1 volt...    if you do not ... try ajusting the gap...  or changing the reluctor....    they do go bad....     it takes 1 volt to trip the power transistor...

i picked up a reman dizzy for a brand F motor... that put out over 4 volts ac... that motor starts really quick...  the old one only put out .70 volts... and was impossable to start...