350 H.O. Components
Short answer: Here’s what set a 1968 350 H.O. apart from a standard 350 (compiled with input from Paul Spotts, formerly of Performance Years):
- Transmission: TH400 (standard 350 autos used the TH350).
- Carburetor: 7029268.
- Heads: different from the standard 350 (#48 heads) — though some 400s reportedly got the 350 #48 heads for more compression, given low 350 H.O. demand.
- Exhaust manifolds: standard manifolds (the long-branch were apparently planned but not used; long-branch would need the oil-filter adapter to clear).
- Valve reliefs: present (the big valves, 2.11 + 1.77, exceed the 3.875″ bore) — possibly on all 350 blocks so the factory didn’t stock two.
- Cam: 067 (auto) / 068 (manual) per the AMA spec (not the 744, despite some claims).
- Power-steering loop: used on cars with high numeric gears (~3.73+).
Note: air shocks weren’t a factory item even in the HD suspension, and the passenger-side “hood scoop” seen in some literature (cold-air induction) appears to have been planned but not produced.
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Content last modified: June 13, 2026 at 10:06 am
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