Great project man, I'm a Vdrive guy so absolutely no help on the jet aspect but I just built a 489 for my day cruiser, the difference between the 489 and 496 is going 30 or 60 over, since I had a clean block I opted to just take 30 out of it just in case I hurt it down the road. I would go all forged and let her rip, look forward to seeing you finish this off.