How is the idle quality with your setup ? I wasn't able to stabilize the idle and have it be respectable with my 502 setup until I went to PFI mode with the '7427. You didn't mention camshaft so that might be a difference.

Your setup is very similar to mine before I went with the 502 , my original 454 was also bored and stroked to 489 , although it wore first a set of Vortec heads then a set of AFR heads and a few different cams .

TOM