Battery Drain?

[AM.MSCL]

My 69 Firebird is now showing issues with battery drain if not started with in a couple of days.
When I got the car it sat for a week between startups, maybe a little longer.
Over the summer I added Vintage Air w/ 3 knob controller, March Serp Kit with 140 amp alt., Electric fan, AutoMeter electric gauges in a Covan's thunderdash, electric choke, blower motor removed, fixed the broken wire for the sending unit in the gas tank, a new power interstate battery; there is not stereo in the car now (factory AM radio did not work). No additional electrical stuff was added that was not already on the car.

We had been driving the car daily for 3-4 weeks after getting everything finished up. We then went on a vacation for about a week and the wife went to start the car one day and the battery was dead. When I get home i checked to make sure A/C was in the off position and lights were off.

I put the charger on the battery for about an hour and she fires right up so we then take her for a drive for a hour with the rpms around 3000 the entire time on the highway (had to go across town to pick up another car). This was Tuesday night and I kept checking the Volt gauge and made sure it was at the 14 mark.

So this morning I planning to take the bird to work and try to start the car and I get fast clicking with the dash lights flickering with the headlights off and A/C off.

I have a volt meter to try and find the drain but want to get suggestions of where to start?
Anyone had this issue after adding something to their car? What was the final issue/solution?
Thanks
Ray