newly built 416 stroker timing adjustments

Everything is new. Started engine and break in at 2500 rpm for 30 minutes. High Z joe gibbs break in oil. Engine runs great but it seems to burn the hell out of my eyes when started in the garage. I don't have my appointment to dyno tune until june 7th.. So today I put my timing light on the motor and started her up. My balancer timing was at 30 degrees BTDC at and idle of about 900 RPM. I should also state that I forgot to remove and plug the vacuum ports on my holley 750 carb?? But that being said I slowly began to rotate the distributor and the smell started to leave. When it got to a point of seeming to want to dive below the 900 RPM I looked at the timing light again and it was now reading about 18 BTDC. Took her out for a spin and it ran real nice. Shut off with no dieseling and started on a dime. So not being an expert here, was it the non plugging of the vacuum ports on the carb that prevented me from getting down lower than the 18 degrees, or was it that I needed to increase the carb idle speed, or is that where the 416 stroker should be or is it a combo of all of the above, which is why I am setting up the dynotune appointment? I don't think I will do any harm to the motor as it is, but I am a little nervous just the same....