Editing Openai/6902a8c8-76f4-8001-a86a-93fe7b5e36c6 (section)

=== Practical recommendations (what to check/do next) ===
# Smooth the U-bend — radius ≥ ~2× runner diameter if possible and blend with the rest of the runner.
# Match runner exits to the head port (and use short, smooth velocity stacks/trumpets at the head entrance if you can). Even small mismatches cost VE.
# Ensure plenum runout is smooth and the throttle plate is centered and free of abrupt step changes. Consider a small velocity step or short entrance trumpet to help distribution if you see uneven fueling.
# Idle control / tune — make sure idle servo/IAC and fueling are tuned after fitment; expect to retune base fueling and ignition timing after manifold/header/cat changes.
# If you want more high-RPM power: shorten the runners (or add trumpet length tuning adapters that are removable), and/or increase plenum volume. If you want to keep the long-runner character but shift power higher, shorten a bit (even a few inches) helps a lot.
# Dyno or data log: final confirmation should be on a dyno or by controlled runs with AFR/logging. The geometry gives a very good prediction, but real VE/flow and transient effects are what determine final numbers.