if you changed the timing gears then the timing is probably off enough to prohibit starting. I've used Phil Singhers method from his VClassics Webzine. It works good and I submit it here: Thanks Phil
Quick and dirty timing:
I prefer to take the distributor out of the car when changing points and condenser. It's a lot easier to do on the bench, and lets me give the whole unit a good look-over. If you're fortunate enough to have access to a distributor machine (getting hard to find in these days of computerized ignition control), it makes it easy to set the dwell perfectly and check the advance mechanism. Here's how to get the distributor back into the car with the timing already close to right.

Before pulling it out, turn the motor so the rotor is pointing at #1 plug wire (that's the forward-most one). Leave it like that until the distributor goes back in. If that's not possible, turn the motor so #1 piston is at TDC on the compression stroke by lining up the zero mark on the crank pulley with the pointer on the timing gear cover. You can tell it's the compression stroke and not the exhaust stroke because both forward valves will be closed -- look through the oil filler cap and see that the rocker arms are even with each other (if your filler is in the middle of the valve cover, pull the cover off).

The pulley is marked at 10 ATDC, 0 (TDC), 10, 20 and 30 BTDC (some also have 40 BTDC). Turn slightly more until your desired timing mark lines up; in other words, if you want to set basic timing at 15 BTDC, the pointer should be midway between the 10 and 20 marks. Now insert the distributor, seat it fully and hook up the points wire. The rotor will point at #1, but we still need to turn the distributor body to the right angle. Turn it counter-clockwise (looking from the top) until you're sure the points are closed. Switch on the ignition. Turn the distributor clockwise until the points just open -- you'll hear and/or see a spark snap across them. Turn off the ignition and tighten up the distributor enough for starting the car. Put rotor and cap back on.

This will get you within two degrees or so of where you need to be; certainly good enough to start the car and permit it to idle. Of course, you'll need to finish up with a timing light to really get it accurate.