440 what am I missing here?

There is nothing wrong with the TF cam....... when used in the correct application.
Which can be said for pretty much any cam.

A cam swap “shouldn’t” require different pushrods provided the base circle diameter of the cam doesn’t change much.

The current cam, run with exhaust manifolds, really isn’t a good match at all for the EFI.
That, combined with the large single plane intake, low stall speed and mild gearing....... and you end up with....... well, you know what you end up with.