These are your words:

"I then shot a 6 pt and got a good pass thru him double lunged".


That alone tells you that you have enough KE to get the job done and it also proves how important shot placement is. Put your bow back down to 60-62 pounds since that is where you're used to shooting it. Stick with the fixed blade broadheads and keep your arrow weight at the 398. Work on accuracy and ways to gain it. Getting the right equipment all matched together helps in many ways with accuracy by adding more forgiveness to your bow. Practice and limit your kill range to what you know you can handle. More KE can be found from these newer bows, but it isn't necessary. You have plenty of KEto do what it takes, just work on putting the shot where it counts.