Sorry I forgot to finish a previous post to Rapid Robert. At the end I was starting to say that the crossover tube requires the angles of the drilled passages to be very specific for it to work. I never performed this because imho it is not diy friendly.
The crossover mod had been misunderstood to the point that it is just a matter of hooking up any old tube and connect it to the other galley. Not so. The angles of the fitting are very important. It should also be mentioned that the originator of the crossover tube is none other than famed Bob Mullen a Chrysler engineer and Bob Glidden. AFAIK this mod was developed for the Mullen designed W2 pro stock motor that Glidden drove. The other thing if my memory serves is that the tube is only one part of the mod.
The number one main is reverse fed from the drivers side galley. This reduced velocity
In the passenger side galley because you don’t have all the oil at number one main
Trying to feed 8 lifter bores on the drivers side. I always viewed tubing the block as easier for the diy person to perform.