Spark Plug Heat range

Pretty much almost most of its existence. Only recall early on in its 1st incarnation it had a bone stock 360 distributor with factory curve and all. Still kb107 pistons. Back then had the 280 mopar cam and 3.55's out back. Now has 3.91's. Any back in its old set up I don't remember it pinging much if any. But that was like 12 or 15 years ago. Fuel was different I think. That cam was a 110° lobe separation vs the 292 purple cam with a 108° lobe.