Hi guys,
I have a 67 frame off that is almost complete and I'm in the process of breaking in the 383.
All components of the car are new including, gauges, painless wiring, gel battery inthe trunk, 1 gauge cable to the starter, 1 wire new alternator etc.

the car runs and drives excelent, however, the battery is being drained by the motor, and if I disconnect one of the battery cables it dies.

any help is appreciated

Sounds like the alterantor is not charging and you're running the engine off the battery. Start by checking the voltage at the battery with everyting hooked up and the engine running. Should be about 14.5v, maybe less with the bat in the trunk and a 1 wire alt. Check it at the back of the alt as well. If it's in the 12v range then you're running on the battery. If you don't have a meter drive it up to an auto parts place and they can check it for you.

and if I disconnect one of the battery cables it dies.
any help is appreciated
For one, you should never disconnect a battery cable while the engine is running, because it can cause a spike in the Alt and could fry the diodes. To determine if the alternator is charging, just do a voltage test as Hank suggests. Test at the alternator and the battery. Another thing about 1 wire alternators is the engine has to be revved to start the alternator, which can be as much as 3500 engine rpm depending on your pulley ratios, see below, taken from powermasters site
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A one wire alternator has a turn on point (sometimes called “cut in”, which is typically 1200 engine RPM’s). This is the speed where the internal sense circuitry connects the battery to the voltage regulator, thereby turning the alternator on. Once the voltage regulator turns on, the alternator will remain on and charging until the engine comes to a complete stop. If the engine idle speed and pulley ratio combination do not allow the alternator to come up to this point during starting, the engine will have to be revved up to turn the one wire alternator on. The sense circuitry in the one-wire regulator can be bypassed to excite the alternator as soon as the ignition switch is turned on. This is called three-wire operation. This means the alternator will not be dependent on reaching a certain turn on RPM.
http://www.powermastermotorsports.com/faq-alternators.html
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You may want to add a voltage gauge in the car so you will know when the alternators working and when it isn't, 1 wire alternators won't work with a idiot light, see here
http://www.madelectrical.com/electricaltech/onewire-threewire.shtml

Thanks guys...
I'll do a voltage test this weekend....
I guess I should rev the motor up to about 1500- 2000 rpm
then check for about 14v at the terminal on the alternator?

I guess I should rev the motor up to about 1500- 2000 rpm
then check for about 14v at the terminal on the alternator?
Correct and also check at the battery. Since your batterys in the trunk and depending on how everything is wired you could still have low voltage at the battery and good voltage at the alternator. You have to have good voltage at the battery for proper charging.