408 6pack setup

Have you verified that your end carbs are opening? And if so, are the end carb throttle plates open all the way when center carb reaches 100% open as well?

Are you running the MOPAR reproduction 6-Pak carbs with vacuum secondaries currently available? If so, were they spec'd (and jetted) for the 340 engine or for the 440 engine?

Are you running the MOPAR over the counter high perf. replacement carbs with mechanical secondaries that were sold by MOPAR dealer in the 1970s to replace and upgrade the OEM 6-Pak vacuum secondary carbs?

Or the Holley Ford type mechanical secondary replacement carbs currently available?

Any of these carbs if functioning correctly should take a 408 cu. in. engine to 5,500 - 6,000 RPMs or more. Even the smaller Ford carbs.

What are the dimensions of your air cleaner filter element(s)?

Exhaust system and size? Type and size of mufflers?

(I'm looking for restrictions to flow.)

Best regards,

Harry