It was more of a chevy thing considering there valve angle was 23 degrees. Older heads could not be angle milled as far, the iron eagle will go far enough to get them down to 21+ degree. But the intake has to be done along with them heads and the heads have to have the bolt holes spot faced to straighten them up also. Then when your done you throw them away lol. More for heads up all out type racing.
The La dodge is 18 degree factory, less is better.
