What do ported heads have to do with it? If you alter the shape of the chamber to produce a slower burn, then you can run more timing. But my chambers havent been altered in shape. Maybe polished, but thats not changing the shape. Ported heads will fill the cylinders more, producing more dynamic compression, which forces you to reduce timing. But add alky and you can get your timing back. The whole point of alky is to add more timing. The burn rate is reduced with alky. High boost/low timing can make stronger mid to top numbers, but lower boost/high timing can increase the average number across the curve, producing a faster car. Ive run 23psi with 27 degrees timing with no problems. The late model stangs...you cant really run more than 14 degrees total timing with boost on pump gas. With 11.5psi, 14 degrees was the max on my cobra. Its because of the higher compression and the fast burn chambers. You add alky to these cars, and you can run over 20 degrees and add almost 100hp at the wheels, without adding ANY boost. And the entire curve will be raised substantially.
You can add more boost, stick to the same timing, and benefit from alky. You can add no more boost, but add timing, and benefit from alky.
