340 cam change

I understand what you’re saying. I had a friend back in the 70’s and his sister’s boyfriend had a 68 340 Dart.
That thing would break the tires loose going down the road 30-40 mph. I remember.
I was only 14 or so. These days I have to wonder if it was an open differential or, was it that bad of a car? Not sure.

There a lot of very knowledgeable engine builders on this forum. I’m sure they will chime in.
Have fun with it!