Les,
You're startin' to make me a bit nervous talking about that rear end change.......slippery slope, my friend!
Anyway, if the butterfly valve has been removed and, presumably the hole plugged, there's nothing to induce an exhaust flow out through the intake manifold anyway, so removal of the added piece won't make any measurable difference. If you aren't having any issues with drivability now, then it wouldn't be worth the hassle of removing the added plate. It's not a fun job to begin with and would net no gain. Removal of it may reveal a surprise, like the real reason why it was put there to begin with.
Contrary to popular belief, the heat-riser ass'y has nothing to do with cold starting because there's no heat until the engine has been running anyway.
Just give that ugly old thing to me and you won't have to worry about it any more!
Frank

Hey Frank...thank you for the reply.. 😆 actually I have her running fairly well...only driven her a half a dozen times and none very far from home. She did place at the 4th of July show :woohoo: and was put on the car show site as their show favorite..anyway I have to make some decisions. ..whether I want drive her as is (with the engine knock) and trailer her if I go anywhere out of town, make some changes so she will go highway speeds, completely customise her...sell her or just bundle her up and look for something that else..
Thank you for all of your help sir..and the ribbing too :whistle:

Les,
I recall the July show but had forgotten aboot the knock......I couldn't hear it from here.
I can't tell you (or anyone) what to do with their own car but I hope you decide to keep it all Hudson.
I don't remember if you have O/D in that car or not. ?? Not as common in the sixes, I don't think.
That's my two bit's worth.
Good luck,
Frank