Reply to "Pistons"

panteradougMember

The B351 pistions are pop-ups. Those are advertised as 11.3:1 but will measure out as about 10.7:1. That is way too much static compression for current pump gas in the US.

9.7:1 actual static compression is about the limit for 93. In some places SUNOCO is advertising that their premium is 94, but not here in NY.

Interestingly enough, I had this issue when we suddenly lost SUNOCO 260 leaded in the pumps around 1976 or 77. I swapped out the high compression heads for the open chamber heads and the engine still was too high for the new unleaded Premium gas.

At one point the detonation was so bad that the engine would misfire and just shut off.

I even tried water injection but it did nothing but bog the engine when "launching" the car.

All the water vapor did was displace the fuel vapor and replace it with water vapor so additionally it was taking power out of the engine.

The '70 high compression pistons are flat tops.

10/15/245:27 AM

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