hard or soft copper line for a valley oil gallery bypass line?

Rapid Robert said
I googled Sanborn (a deceased guru here on FABO) & there is some heated pro & con conversations regarding this. I will dig in further & definitely give alot of thought/weight to your info. thank you. RR

Duane said
Hey Robert. I am a firm believer that the crossover mod works to slow oil velocity, when properly done. Having said that, I have never done that method because the angles that you are asking about have to be done right or it doesn’t work. Imho it is not a diy
Job. I found the tubing of the main gallery
Easier for a diy to perform.
The crossover mod has evolved to where sisters think it is just a matter of putting in two fitting and connecting any old tube.
That is why

Thankyou. Although I do agree with one part of his explanation. Feeding both ends cut the flow in the galley. Which is exactly what is desired. The pressurized oil has nowhere to go but to the low pressure area at the bearings, which is exactly what we want. The problem with the stock system, is there are too many other places for the oil to go.

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.