Quote:
Originally Posted by David Brown
My 455 originally had #15 heads. I have owned this car since 1979, when "real" high octane leaded gas was still available. When they phased it out leaded and replaced it with 93 octane unleaded, I had a continual pinging problem. I struggled with that for a couple years. Back off the timing and it ran hot. Octane boosters were for the most part snake oil. For a street driven car, it was a major pain to be constantly chasing the right sweet spot to eliminate the ping and not kill performance. The only fix was head replacement to lower compression. I ran 1971 #96 and they were great until previous repaired cracks let loose. Now I run 6X and have about 9.25 to 1. . If you plan a compression increase, make sure you get a cam that will control the pre-ignition. If it's for the strip, then you probably will buy race gas.
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Does your engine still have the stock cam in it??? Just wondering...how does it perform with the 6X heads?
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1977 Black Trans Am 180 HP Auto, essentially base model T/A.
I'm the original owner, purchased May 7, 1977.
Shut it off
Shut it off
Buddy, I just shut your Prius down... 
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