What stall converter?

Contrary to what some in here say, the 474 may be small on lift, it's approximately 238 at .050 duration cam. That's NOT small and would like more than a stock converter. I'd run a good 3000-3500 that is built tight on cruise. Not some off the shelf slop converter.

Advancing the cam, ahead from the 106 ICL, would help with bottom end performance.

Get the tune up right, not enough initial timing sounds like a possible issue.