289 wont start

I have a 65 mustang with a 289 2v, it ran ok before i decided to change the points, condenser, rotor and distributor cap.  After i replaced those items the car will not start, it made one loud pop and that was it.  I put the old items back on and still will not start.  I checked the coil for spark and it appears ok, I checked for spark on the points and it sparks as well but does not look very strong but Im not sure how strong those sparks should be.  I tried to turn the distributor a little to play with the timing but the distributore will not budge, how can i brake that loose??  Please any help to get this thing running again would be great>  

The car seems to have backfired after you replaced the ignition parts you mentioned.
If it ran good before then one of the new parts or wires was installed incorrectly or changed the timing.

Loosen or remove the distributor hold down clamp and put a small flat blade screw driver between the disrtibutor and the block to gently pry it upward slightly about an 1/8 inch and rotate. Not too far since your oil pump drive rod runs beween the oil pump and bottom of the distributor. Squirt a little WD-40 around the dist base where it enters the block. You should then be able to rotate the distributor body.
 
Remove a spark plug and attach the plug wire to it and ground the plug to the engine block to observe the spark. It should be a strong blue/white spark. If it is a weak looking yellow or orange spark then you may have a weak coil.

Check your carbs choke to be sure the backfire didn't jam the choke plate completely shut. That will prevent the motor from starting too. Look there first.

If things still aren't working for you be sure you didn't jump or break a timing chain during the backfire. All your valves should open and close properly by viewing them with the valve cover off. If none of them do when you rotate the engine or crankshaft then you broke a timing chain. If they do move then both valves should be closed on the number one cylinder at TDC on the compression stroke. If not then the chain may have jumped a tooth and caused a cam timing issue. More likely a bad ignition component or jammed choke but you never know.

Also read the Forum post "distributor problem". It may be related to your issue.  

You may have also miswired the dist cap. Go back and verify the plug wires match the firing order and are correct on the cap. jlg  

I tried everything that everyone has said to no avail...i dont think the timing chain broke due to the fact that i can not hear it flopping around while trying to crank the car.  I get intermitent spark on the #1 cylinder, and i keep getting a terrible back fire that is coming out of the carb, not the exhaust. I am at my wits end and dont know what else to do.  any other ideas please help  

If you broke a timing chain your valves won't move and neither will your distributor rotor since it is driven off of the camshaft. A broken chain will sometimes just collapse and fall into the oil pan so you won't be able to hear it.
Check to be sure your distributor rotor is moving by removing the distributor cap and turning the engine over. Also make note of the direction the rotor turns when doing this since your firing order and plug wires will established in the direction of that rotation.
A carb backfire means the engine is igniting a cylinder when the intake valve is still open incicating that the timing is off or the firing order is wrong or the cam has jumped. Probably one of the first two if the distributor rotor is still turning.  

As correctly stated, backfiring thru the carb on start is a timing issue. Take a breath and go back to square one.
1. check point gap or dwell ( 0.17 gap on the high point or 26-32 dwell)
2. check dist cap is wired correctly.
3. put #1 cyl on TDC (compression) and verify that the dist rotor is pointing at the #1 plug wire tower(or just a little before it).
4. if 1-4 are good the timing chain has jumped. (It happens that quick sometimes with the old plastic toothed cam gears)  

I actually got it running great....thanks for all the help.....I put clinder 1 at TDC and the rotor button was aimed at the number 3 on the distributor cap.  I rewired the distributor cap to match this and it worked great, tomorrow I will pull the distributor and line it up properly.  Im new to this and I am learning a lot in a short time, thanks again  

Good news! Good work on troubleshhoting your problem. BTW: Be very careful if you
absolutely have to "pull" the distributor out. Make sure you keep the rod that drives the oil pump from pulling out and dropping into the oil pan. It slides into the very bottom of the distributor and the other end goes into the oil pump several inches directly below. If you have to realign the distributor try to just move it upward slightly so the drive rod doesn't come completely out of its sockets at either end. Then hold the rotor in place pointing at where your NO.1 distributor cap wire terminal would be and rotate the distributor base to get the vacuum can pointed slightly toward the top radiator hose from off center. Be sure to double check all your plug wires are oriented correctly again. If you pull the distributor completely out you may have some issues getting it back in. Avoid that if you can.
Good luck and enjoy your ride.  

The sound of the oil pump drive shaft dropping into the oil pan is very depressing.  

thanks for all the help, I have decided against even messing with the distributor because there is really no reason too.  The car is running great.