Factory Cast-Aluminum Intake Manifold Comparison - Intake Uptake Revisited
What About Casting No. 485640?
Few are aware that two different casting numbers were used for the cast-aluminum manifold found on '72 455 H.O. engines: Nos. 485640 and 488945. It's rumored that No. 485640 was an experimental piece used during Super-Duty 455 development. Our research suggests that No. 485640 was in fact a production 455 H.O. piece used early in the '72 model year. It was replaced by No. 488945 midyear for unknown reasons. A visual inspection of the two manifolds reveals that the castings are identical in every respect, and that No. 485640 contains the lesser deep-plenum floor height. -RR View Related Article
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