Stock 340 manifolds value
The 60's ones had a heat shield to protect wires. Of course those shield repros are like $200
The 70's casting has a reduced cross sectional area in the log that collects exhaust gas from the 1st, 2nd and 3nd cylinders.
It might be a very small amount, but the 72-up has to be less HP. That amount of HP difference will very per cubic inch, cam, HP, rpm, etc.
68-70 Hi-Po driver manifolds.
72-up Hi-Po driver exhaust manifold.
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The 60's ones had a heat shield to protect wires. Of course those shield repros are like $200
The 70's casting has a reduced cross sectional area in the log that collects exhaust gas from the 1st, 2nd and 3nd cylinders.
It might be a very small amount, but the 72-up has to be less HP. That amount of HP difference will very per cubic inch, cam, HP, rpm, etc.
68-70 Hi-Po driver manifolds.
72-up Hi-Po driver exhaust manifold.
