ok need help at my wits end

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I can't seem to pick up my truck anymore, I know it can't be maxed out. LOL

My engine is very similar to super73 new 418.
This summer in the heat it has been running 11.20's at 116. I have tried several things to make it back to the 10's in the heat but nothing is changing, runs the same.

I bought another converter that is supposed to be 300 rpms looser, but it doesn't feel any different and kinda acts strange. If I shift at 6500 the rpm drops to 54-5500, or if I shift at 7000 it still drops back the same.
The truck runs the same with this converter

I put a new bigger carb (sv1) and nothing has changed, runs exactly the same.

I put new bigger headers, went from 1 5/8 tri ys, to 1 7/8 stepped to 2" long tubes. Truck runs the exact same if I shift at 6500 where I allways shift, but now it likes 7000 and picked up a .10 and 1 mph.

I do have full exhaust. 3" and dynomax ultraflows but I don't think they are a restriction. The ultraflows are straight through.

Last I have done is get another converter, this one will drop to 5800 if I shift at 6500, and drop to 6200 if I shift at 7000. I have not been to the track with this converter yet. All of the converters have been ptc.

The tune looks good, little on the safe side. Really needs about 2 more degrees of timing.

I don't know what else to do. I need about 2-3 tenths more. I want to do this all motor with no power adders.