The 920 heads have 1.87 intake valves and the other one has 1.78's. The 920's were used on the w/CAP (clean air package) engines. They were also used on the D/Darts which had a version of the W/CAP engines in them.
Back when I posted this, I had already sold my one D/Dart and was going off the valve sizes posted in Galen's Casting Book -- 6th printing -- Jan 1996. D/Darts had 273 w/C.A.P. engines in them. The intake number is casting number 2536771 and according to Galen's book, the valves on the 920 heads w/C.A.P. are 1.87 x 1.50's which is incorrect. Per all the info that I have from Chrysler, the standard valve gear was used on the cars. Heavier valve springs were used, however, which permits higher engine speeds. It was not advised to operate the engines over 7400 RPM's.
