The engine builder replaced the bent push rods, and replaced the original rockers with some expensive crane rockers. It’s running better now, or at least on 8 cylinders anyway. It still needs to gone through and have the timing set up, carb, etc. I can tell you this, the Whiplash cam does have an extremely radical idle. Here is a video of the stock 383 running with long tube headers, 3” dual exhaust, h-pipe, and flow master super 10 mufflers.
https://www.youtube.com/watch?v=TvqFPA7H9FMHere is a video of the 440 with the exact same exhaust system. It’s a little hard to tell in the videos, but the 383 was surprisingly quiet and reserved with this exhaust system. The 440 however is insanely loud. It honestly sounds like open headers, it sounds like a drag car. Every time I fire it up my neighbors all come to their windows to see what the noise is all about. Apparently it actually shakes the windows of the house directly across from us, lol.
https://www.youtube.com/watch?v=KBkYMN-aPhM