I picked up an old GMC truck that came with a 350 and carb. So I naturally slapped a junkyard 7747 on it and it's running ok.

I'm running a GM 7pin module inside a stock GM HEI. When I put a timing light on it, the timing marks are rock solid and don't move. This is with the bypass plug connected or disconnected. When I rev the engine the timing marks do go up about 5-10 degrees and that's it.

Shouldn't the timing marks advance more than a few degrees? IIRC the marks should be 'jumpy' at idle with the bypass plug connected.

Running a stock ASDU bin.