NHRA Horsepower Ratings for the 273
R/T,
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Camcraft Camshaft .495/.505 Lift - 284* Duration - 60* Overlap
Racer Brown #VR-18X Valve Springs - #313 lbs. @ 1.05" (Open) and #150 lbs. @ 1.55" (Closed)
Cast Iron Intake Manifold - Throttle bore openings opened up to 1 11/16"
Aluminum-plate carburetor adaptor.
Holley Model #4160 / List #3778 - 700 CFM Carburetor (Factory Modified)
(1 11/16" Primary / 1 11/16" Secondary) - (Venturies 1 5/16" x 1 3/8")
Dual-Point Distributor, w/Vacuum advanced removed, and pre-set to 35* Total Advanced