[1969GPSJ]

Originally Posted by Cliff R

"428 HOs didn't have special pistons."

The last 428 that I built here was a 390hp version. It had special exhaust manifolds, oil filter adapter, and something different about the harmonic balancer (maybe much wider than the standard variety?) and the big valve heads with screw in studs. It had the same crankshaft, rods and pistons as the 360 and 370hp engines nearly as I can remember. I know for sure they were dished and far as I know that engine had never been apart before I got to it.

I'll add something not well known about 428 engines. They made several different crankshafts for them, early were Arma-Steel, later were "N" cranks. One of the casting numbers is prone to cracking, pretty sure it was the one used on the 1969 360hp engines. I broke one here, and in my search for a replacement (they weren't easy to find 30 years ago) I found several others cracked in exactly the same place. One I obtained looked just fine and when I took it to the machine shop they spun it up and it was wobbling ever so slightly. The machinst hit it with a BFH and it broke into two pieces right in front of us!

He didn't act surprised at all and said he'd ran into a number of them over the years with that issue......FWIW.......

Thanks for the Reply Cliff! Your replies pretty much put together all of the pieces that others had mentioned, and likely helped me come up with an improved "anti knock" interim plan for my 428. The pros vs the cons of thicker head gaskets discussion helped. I am going to change the cam, so far I am leaning in the direction of the 744 or 041 cam. The 068 just seems a little too light, and I really liked a crane cams (RIP) energizer 288 that I used many years ago - it was kind of in between the 744 and 041 spec wise. The heads have to come off anyway, so I'll change the springs, upgrade the studs to BBC style studs, add an adjustable valve train, and that should suffice until I do my more extensive engine build. By the way, Cliff, look at my reply to 242177P's post and you will see why I had thought that the 428 HO pistons were supposed to be flat tops (without the dish). '69 Service manual led me astray - check page 6-40. Thanks go to Cliff, HWYSTR455, Gach, and everyone else who contributed to this thread!