Magnum and Wiring Swap

Up until yesterday, I had not driven the car. I got it together enough for a test drive. Initially it fumbled and misfired going up a hill and I thought I was going to bring it back to the house. But it cleared up and started running better. Good enough to drive around some more.
It has a hard time going from idle to about 1,500 RPM. Almost like it surges up and down before getting past it. It does have a Comp Cams Xtreme Energy .484 backed to a stock 904 and convertor. I wouldn't think that would be too much cam a stock convertor.
Also when I put a timing light on it, the timing fluctuates 5-10* at idle. I thought that was odd. It has a new timing chain and the distributor hold down bolt is tight.