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for you guys that have dynoed your combo. what afr did it make the most power? say if 12.5 is best at sea level. then is 12.5 still best at 5000'. unfortunatly mine is 5000'.
 

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Unfortunatly air fuel only accounts for ~7% of power between the point it is so lean that it is starting to break up, to the point it is so rich it is starting to break up. The real power loss comes in well after that. WAY to rich/lean and breaking up you will certinatly loose power, but if it runs well and is safe don't fuss with it. Get the car to run well, and safe and you will be near your best air fuel ratio for max power. Instead, focus on your timing advance.
 

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The head that will give you the best power is going to be the one that has the ports, valves and chambers with the air flow necessary to match your cam, compression ratio and exhaust system.
The head that gives you the best HP at sea level will be the same as the one that gives you the best HP at 5000 feet - whether you are running supercharged or naturally aspirated.
Paul
 

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I dynoed my car earlier in 2006 and did some jetting during the session. However, it didn't make as much difference as I thought it would. In taking the afr from 11.65 to 12.72, I only gained 2.1 HP.

However, by adjusting the timing from 36 to 38 I gained 6 HP.
 

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Oh, I forgot to mention that this dyno session was at 5000', and I run at Bandimere which is at 5800' elevation. So you should be shooting for the same afr you would regardless of your elevation.
 
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