On mine I soldered shut the OE holes in the side of the shaft (kept the OE bottom ones) & redrilled thru the rocker (.100") & on thru the shaft on the valve tip side and thru the shaft on the pushrod side (the rocker already has a hole on that side then I brazed shut the hole in the top & plugged the large access hole in the rocker on the pushrod side that is already there & I drill the new ones with the cam on base circle so there is some dwell time for a good flow.