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Old 08-06-2009, 05:04 AM
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Originally Posted by 66Ponty
Moving to the cooler plugs did help a noticeable amount.

Would jetting help with the pinging? I actually thought that it might be pumping too much fuel, as was the reason for getting the regulator. That was speculation though. I do get a strong odor of gas sometimes when I open the hood after running the engine and shutting it down. A bit more then I used to with my old engine.

I still need to pic up my cam spec sheet
Don't confuse fuel pressure with jetting. Jetting will allow more fuel into the fuel/air mixture that enters the engine to make power, totally different than fuel pressure that supplies the carb's float bowl, although excessive fuel pressure can cause the fuel level to become too high in some cases, and this will cause the engine to run rich- but for different reasons than larger jets. You really need a gage to determine what the pressure is, not arbitrary numbers on the regulator that have no correlation w/any real PSI figure.

When you mention heads from a '68 GTO, what you need to say is what "number" the heads are (the number is found cast onto the center exhaust port, will be 16, 31, 96, etc.). For '68, for instance, a GTO could have had several different heads, depending. But they all will have combustion chambers around 72cc, give or take.

If you don't want to change heads or pistons to lower the CR, you will need to tailor the advance curve, total timing and carb tune, as well as run the best available pump gas, 92 octane or whatever premium is in your area.

A cam change could help matters, if the CR is too high to work with- like if the heads have been excessively milled, or are being used w/domed pistons for some unknown reason (Pontiacs from the factory used combustion chamber volume to change the CR).

The cam timing has something to do w/how the engine will tolerate pump gas, too. You need to find the spec's on the cam.
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