Originally Posted by Cab_Burge
The smaller the needle and seats will allow more pressure before being held open by the fuel pressure. The Holley brand needle and seats .090 will hold 9.5 lbs. pressure is what I have used in the past, the .130 won't hold much above 7/0 lbs. pressure. twocents scope
many decades ago i was taught larger needles and seats tolerate more pressure; that is wrong! smaller needle and seats are far more manageable.