oh f*%k

Use the 3/8" pickup. I've run a 3/8" on my 850 HP 500" engine spinning it to 7,200 rpm.
years ago i ran a 383 with 3/8 pickup to 7500 for 350 1/4 mile passes with no problems. the 493 is a bit more serious of a build and don't want the engine so don't mind going to a external line.