Good news,

I got the vortec heads back from the shop, magnafluxing showed no detectable cracks. To minimize the possibility of having the rocker arm studs back out under hard use or higher valve lift, I decided to drill and pin the studs in place. Some people have suggested drilling, tapping and install new screw in studs, but the pinning idea seemed to be more economical and plenty good for my mild build. My intended cam will have only a .500" lift with typical roller lifter ramp speeds.

I picked up a pin kit from Mr Gasket that consisted of 16 roll pins and a drill bit for $13.


With the high sides on the vortec heads it is just about impossible to drill the risers at 90 degrees to the studs and locate the hole 9/16" down from the top per the instructions that came with the kit. By mounting the head in the mill at a slight angle, and positioning the drill bit tight up against the head railing, I was able to start the holes from one side about 3/8" down and to angle the hole so it came out the other side at about the 9/16" position.


The original bit that came with the kit lasted about 2-1/2 holes using good pressure and lots of oil before the tip ground down or chippped to the point and wouldn't drill any more.


I had bought a couple extra titanium coated ones just in case as I had heard from others, that I would need to either have extras or do a lot of resharpening. The first titanium bit worked just fine for the remaining 14 holes.


With the head still clamped in the mill, I tapped the roll pins in. The instructions say to position them so the end nearest the valve is flush, but I found the entire length of each pin was almost exactly the same as the riser width so they mostly ended up with both ends flush.



Here's a shot showing the side closer to the valve


With all the pins successfully in place, I spent some time running a tap and cleaning out all the threads in each head. Looks like my next job is to clean them up thoroughly and reassemble the valves, springs, and rockers. I understand I should probably look into purchasing all new locking retainer nuts for the rockers.