A Victor Jr's runners are too small to run on a 421 especially with large runner heads like those, you will waste your money sending the heads out. Here is a guy that will do a great job at a reasonable price and can discuss a better intake like a Super Victor.
Speier Racing Heads
420 East 8th
Hays, KS. 67601
785 628-6673
Chad also runs this site.
http://www.1320techtalk.com/