Does the Sanger have a Berkley jet in it ? A good improvement would be a aluminum manifold ,a performer would be best to keep the low end torque you need .A holley 750 3310 would also work great , Holley's alway's seem to have the low end grunt as apposed to the Rochester with huge Primaries .I ran a 600 on my 327 , with a performer it was awesome !!!Does the 454 have a thermostat kit in it. It really helped mine out .