Rich idle, would this help?

The blocks don't matter. The mods they are doing are bringing the billet blocks as close to the stock old style blocks as possible.

I've got an Old 850 DP. If you read the thread a couple times you will see that those pros mention there is absolutly no advantage using a billet block over a factory block. Lol , the after market sell foo foo parts to make $$ is the deal!

As far as modding the factory blocks yes you can. I just ordered all the stuff to do just that. Drills, Taps, brass plugs, pin gauges & pin vice drill set.

If you want KMJ performance sells blocks ready and tapped for 44$, you would still need to drill and tap the main body for the idle and main air bleeds.