AFR Tuning- Old skool vs. New school

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Salty Crusty

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Texas
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Gary
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1986
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c1500
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565
Old was "school", new is skool.

Us old farts are purists when it comes to the way we talked and wrote back in the day.

And trust the AFR gauge as long as its from a reputable company.
 

75gmck25

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Bruce
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1975
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K25 Camper Special TH350 NP203
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5.7
I guess it works different for various engine combos. However, my dsitributor is supposed to be the same one used on the ZZ4 base motor and I use manifold vacuum for the vacuum advance line. I have a 350 with Blueprint 64cc aluminum heads and use about 15-16 degrees base timing and 20 degrees mechanical. My cam is 213/217 @ .050. AFR runs about 13 at idle, but jumps around a bit. At cruise its usually about 15.5-15.9. Getting stable AFR with an old Quadrajet has been challenging.

I did switch to a vacuum can with less total advance (around 14-15), since the original gave me about 22 degrees advance. I've always been told that not running vacuum advance will really lower highway gas mileage. I use 87 octane gas and have heard no pinging.

Bruce
 

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