Ram Air III Long Branch Manifolds
Short answer: The 1969 Ram Air III “Long Branch” cast-iron manifolds are a smart choice over headers — better flow than log manifolds, a more reliable seal, better ground clearance than headers, and less noise and underhood heat (headers cook the starter/solenoid in a Firebird).
- Oil-filter clearance: they require the angled oil-filter adapter (~$75). Even then you typically slide the filter down the frame a few inches to clear; some drop the exhaust pipe or fit a remote filter. (These are factory manifolds, so it can be worked out at install — point it out to your exhaust shop.)
- Porting: to match ported heads, open the manifold inlets — about .060–.090″ off the top of each port.
- Repro: available from Year One (2.25–2.5″ outlets), though you may need to source the flanges separately; have them hi-temp/ceramic coated.
- Skip extrude honing — it’s very expensive (custom coated headers would be wiser money). Add a starter/solenoid heat shield (as GM did with these manifolds).
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Content last modified: June 13, 2026 at 10:06 am
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