Iv been tuning my new 421 from vito's, And i put the laser on both pipes to see the how hot they were, and the left side (shifter side) runs about 60-80 degreese hotter then the right side ( Brake Pedal side) ?? Carbs are in sync, same jets on both sides, plugs are gapped the same, Im not sure why they are so much different ? Also i can tell by the plugs the Hotter side is nicely browning up, and the other side is more darker. Anyone eles have this problem? ? My engine only has about 10 minutes of run time on it, and its not yet perfectly tuned. But i would think they should be closer temperature wise.