392,
Mine has the 4.03 bore and a stroke of 4.075 for 416. I have had it since 1996 and no problems. A friend of mne has his at 410 and he went with all light weight rotating assembly and said he sometimes wishes he had stayed with the steel like I did. We both mostly drive on the streets and I have great compression when we are coming down off the mountains and hardly ever touch my brakes and he has to be on his most of the way down. But his will wind up faster than mine does. And he has more horsepower than I do. As for if you will gain a lot by going up to these cubes, I really don't think so unless you just want to. Just my .02¢ worth.
Ron
