Offenhauser Dual-Port 360* Intake ~ 'Was It A Gimmick'

Offenhauser 'Dual-Port' 360* Dual-Plane/High-Rise Intake Manifold's

#6005-DP ....... 340-360 'Square Bore'
#6006-DP ....... 340-360 'Spread-Bore'

#GOQO-DP ...... 273-318 'Square-Bore'
#6021-DP ........ 273-318 'Spread-Bore

~ Improvement Trick ~

Cut {grind} out 1" of the Split-Divider in the Intake Runner from the Cylinder Head
side of the Manifold.

Also, smooth out the flashing-edges in the Runner-Ports near the Cylinder Head side of the
Manifold.

A 'definite-must' is to Gasket-Match the Intake Manifold ports, and with a smooth-finish
at a minimum-depth of 1" into the Runner-Ports.

Result, worth an additional {+15 HP} at 4500 RPM's.