The S&S manifold conversion kits for Harley-Davidson Evolution and big twin engines are designed to replace the original rubber "compliance fitting" style manifold and seals used on 1984-1989 big twins, with a rigid mount aluminum manifold.
The stock style rubber compliance fittings, used in this range of model years, are subject to degradation due to heat, age, and exposure to petroleum products. Intake leaks are a common problem with the compliance fittings due to cracks in the rubber. The most common symptom of an intake leak is an erratic idle, but intake leaks can cause poor overall performance, and in extreme cases, can cause serious engine damage due to a lean mixture in one or both cylinders. By upgrading to the S&S rigid mount manifold, these cracking and leaking problems are eliminated. In addition, the improved flow of the S&S manifold can help improve performance.
Since the S&S manifold conversion kit is intended to replace the intake system on stock engines, the manifold provided in the kit is machined to the correct length for a stock displacement engine. The manifold included in the conversion kit is the same one used in S&S Super B and E carb kits and is machined with a 1-7/8" throat diameter.
S&S Model # 16-1658