340 Engine Power Boosts

Discussion in 'First Generation Challenger Forum' started by SRT-Tom, Apr 5, 2020.

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  1. Apr 6, 2020 at 6:00 PM #11
    SRT-Tom

    SRT-Tom Well-Known Member Staff Member Super Moderator Article Writer

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    Holley made a great carb. However, my 1971 340 'Cuda ran great with the stock Carter Thermo-Quad.

    The Thermoquad was unique in carburetor design in that it was the only carb that was originally designed as a race only carb, and then because of its success, de-tuned for street/O.E. use.

    Many thought of the TQ as the "perfect Quadrajet"; since the TQ retained the good points of the Q-Jet, redesigned the bad points of the Q-Jet, and added the thermoplastic bodies. Carter had tests done by different independent testing facilities, that found the temperature of the fuel in the TQ bowl, on average, was 28 degrees F. lower than the temperature of fuel in the bowls of all metal carburetors.

    Since the rule of thumb is that a reduction of 10 degrees F. fuel temperature is a 1 percent increase in both power and fuel economy; it is easy to see the advantage of the TQ. Everything else equal, the TQ was 3% better than other carburetors. Could you feel 3% on the street? Probably not, but the racers could measure the difference; and a 3% increase in fuel economy on a production vehicle helped.
     
    Last edited: Apr 6, 2020
  2. Apr 6, 2020 at 7:27 PM #12
    Katshot

    Katshot Full Access Member

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    Not sure who you think referred to the TQ as the perfect Q-Jet. It wasn't. It was designed to compete with the Q-Jet but in my opinion, it was an overly complicated design that suffered from cracking and warping of the plastic (phenolic) body. The only thing I ever liked about it was the sound it made at WOT.
     
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