Well a"built 904" has a low gear of
2.45.Together they have a starter gear of
8.79. That 268 cam,Is known to be soft on the bottom unless the cylinder pressure is quite high.With a
2200/2500 TC, I'm guessing it will be right up the middle, on that engine
This all conspires to
possibly make a disappointing blast off the line.
Assuming the TC is a done deal, and on it's way; To ease your disappointment, I suggest cranking up the compression to the maximum for your gas.With alloy heads, this might be in the range of 10.4 to 10.8
Altho, with a 408, a soft bottom end might actually be a good thing.
I like the 3.21s;
At the top of first gear they will hit 60 mph at about 6200,with 27 inch tires and 5% slip.
At 32 mph, the 408 will be doing 3307, just below it's torque peak, which will probably show up at about 36 mph. You are gonna need serious rubber, an LSD, and a traction aider.
65mph will be about 2600,not too bad.
This is shaping up to a very nice combo.