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Reply to "Pantera # 5357 - Rocky's 1973 L model"

You guys are funny. Irritating too.

It's very easy to spend somebody else's money.

All the choices in my car are a trade between performance, budget, amount of labor to install and getting the parts to fit in the vehicle while retaining a relatively stock engine bay, that can have a tub in it.

Nevertheless, I am willing to have a more scientific discussion on the current state of my engine.

Yes, I had all the spark plug wires installed.

The carb is now a Holley List 4609, modified for 4 corner idle, and has quite a bit of work done to it. 735 CFM.

Holley 4609

Yes, it is currently set up with a vacuum secondary carb. Previously, I was running a Braswell double pumper racing carb, with mechanical secondaries, and no choke or choke horn. This was swapped because:

  • It wasn't mine
  • It was a PIA to start every time with no choke

    Testing on the dyno showed a constant vacuum across the venturis through the RPM range (3000 - 6000). The engine is not running out of carburetor.

    Testing on the dyno indicates that once the engine was making peak horsepower, changes to jet sizing, and changes to timing had very minor effects on the power, yet fuel consumption could change relatively significantly.

    My builder is also convinced that the restriction is in the collector in the header. This was determined by testing without the tailpipes (enlarged) and the ANSAs.

    You can see the modifications already performed to my exhaust in this thread, and the link below also implies the "standard" Hall Headers are not optimal. Sorry about the missing photos...

    ANSA MPS-1 Modificaiton

    Joules Comments on Collectors

    Anyway - The motor is off the dyno. I have a lot of work to do to get the motor back in the car.

    I am happy with what I have done.

    I will hold off on installing the headers till near the end of the project. I am sure that by that time, this group will have "crowdsourced" me the ~2500 it will take to buy the correct Pat M. or Pantera Pro-Formance headers and exhaust that will unlock my missing 30 HP. PM me for PayPal instructions.

    Likely, I will have enough donations to get a set of both. If you guys do that for me, I promise to post up a review of each configuration. This will allow you all to criticize other aspects of my build.

  • Last edited by rocky