Quote: I've also supported 550hp with a factory mechanical and 5/16 line. Many lines now have kinks and guy dont cut them properly so the flow is much lower than it should be. That fact is, overkill sells, and in many cases, meaning a car that runs in the 12s or high 11s, they simply dont need that much pump or line. In somecases, you add so much volume in the line the milder pumps have trouble pumping against the inertia of the fuel in the line in first gear.
There have been many threads on that subject. There is also the matter of friction loss in the lines. The more pressure you force through the line the higher the friction loss.
