The way to give that 350 more bottom end (or at last feel like it) is to put a steeper gear in the rear end.
The beauty of the 455 is that it'll have tons of torque just about any way you build it. Even with highway gears it'll still roast the tires any time you want.
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1966 GTO
1969 Lemans Convertible- F.A.S.T. legal family cruiser. 12.59 on G70-14 Polyglas tires. 1.78 60'
1969 Bonneville Safari- cross country family cruiser. .
1979 Trans Am 400, 4-speed, 4 wheel disc.
View from the drivers seat racing down Atco Raceway-
http://www.youtube.com/watch?v=GhYDMdOEC7A
Ride along in the other lane-
http://www.youtube.com/watch?v=mIzgpLtF_uw