Good info from Cab. Years ago I put a Hemi 1/2" pick up tube I'm my 440, block was drilled and tapped for the larger tube. I spun bearings in two engines before I discovered this; the pick up tube had a 2 1/2"long hairline crack just above where the bend was for the screen. Only reason I found it was because after the second time I was cleaning the tube in a parts washer, I submerged the tube & screen in the cleaning fluid, lifted it up out and had each end covered by my hands as I shook it back & forth to make sure all the filings were out of the tube and fluid was coming out the side of the tube where the crack was. That F'ing crack cost me two engines. Might be worth looking for.