Below 1 rocker stand on each head is the
oil feeder to the rocker shaft, this is where to restrict the
oil there are several ways to do it the most common being with a small puck drilled out to .090 then pressed or just tapped in with a small hammer, I had mine drilled and tapped during the head rebuild so i could use screw in restrictors. As far as the deiseling goes, in my opinion if the
oil restriction caused heat build up enough to cause deiseling then the valve train is toast. I think thats a false statement. Anyhow no problems with mine and would do it again for sure and highly recomend it.