closed chamber vs open chamber

Here we go again. Here is the dyno difference on a 440 between a set of stock 906 heads and a ported set of 516 heads flowing.......

Lift............In/Ex

.100........85/62
.200......160/132
.300......210/182
.400......237.203
.500......250/216
.600......261/229

RPM...............906 TQ/HP.............516 TQ/HP

3000................431/246...............434/248
3500................441/294...............458/305
4000................438/333...............450/343
4200................444/355 ......................................peak torque w/906
4500................434/370...............470/402
4600.............................................473/414..........peak to peak TQ w/516 +29 lb-ft
4900................415/387.......................................peak horsepower w/906
5000................405/386................457/437
5300.............................................445/449..........peak to peak HP w/516 +62 HP
5400................361/372................428/440.........+67lb-ft/+68 HP
5500..................NA/NA..................421/441
5600..................NA/NA..................407/434
5700..................NA/NA..................397/431
5800..................NA/NA..................391/432