[Dick Boneske]

If your Tri-Power ran well with the 400 engine, but you're going to 459 cubic inches and a healthy hydraulic roller, the carbs need to be calibrated to work with that combo. If you provide cam specs, I can guide you through carb calibration, or you can send me the carbs and I'll do the calibration in my shop.

Basicallly , the changes needed are---idle tubes enlarged from .032" now to about .046". Idle bypass restrictors (stock is .043" or .046") to be enlarged to about .052". Center carb jets about .063" End carb jets .071" or .073". Throttle base idle adj. holes enlarged to .078". If the cam is fairly radical, the center carb throttle plates need to have holes to allow idle position to be proper for idle circuit.

Send me the cam specs, and we'll zero in on exact changes needed.