[asphaltgambler]

I don't know your cams exact specs but 10:5 - 1 is pretty standard with any high performance street cam as the increased duration and overlap will bleed some of that added cylinder pressure away. Additionally the cylinders and heads are (obviously) made from aluminum so there is added heat loss which results in lower combustion chamber temperatures.

Also if you have not replaced your ignition module with an aftermarket adjustable timing unit, you will need to at this stage. By twin plugging you should be able to pull back total ignition timing by @2 degrees which does not sound like much but it will make more power on the top end with less timing using two flame fronts.


Your stock carb will work but will need re-jetted. With that said you should also consider adding a Thunder-jet to your carb for the added rpm's and increased air flow. It is add on 3rd; high speed fuel circuit for your carb. Zippers developed this and hold several patents. I can have installed many and I consider a must do item on any performance HD. The 411 on the Thunderjets are on Zippers webpage.