distributor help!

[fwdstuck]

I bought a new distributor cap, off of ebay (a red one) to replace my old cap(a black one) because it was missfiring. When I put the new one. It wouldn't run. So I put the black one back on and it wouldn't run ether. But it ran great earlier that day with the old one on (just missing a little). I don't know what I have done to it. I notice that the part from the cap that touchs the rotor button are alot diffrent in shape between the red one and black one. i need some help. thanks

[fwdstuck]

Now I need to test the coil to see if that is the problem. Does anyone know how to check with a ohm meter with it out of the distributor? Thanks

[fwdstuck]

I just checked it with an ohm meter. I'm geting 0 ohms between the primary and 15,000ohms between the secondary. Can anyone tell me if it is bad. Thanks

[brute4c]

Coil tests are on this page:

http://www.m715zone.com/vb/view.php?pg=24_tuneup

and in the ignition section of this page:

http://www.m715zone.com/vb/view.php?pg=20chap2-6