Thornton’s 350 JR Exhaust Manifolds




Brand New, Custom Design!

Here is a high performance exhaust manifold that GM never produced. We have produced what everybody was asking for. This is the high performance solution instead of headers.


  • Large 2 1/4″ outlet on the driver and passenger side manifolds (original stock manifold is 2″)
  • No crossover pipe hole to plug on the passenger side
  • Divided center port design
  • Larger design for better air flow
  • Direct bolt on with no modifications needed

These manifolds were conformed from the 1970 455 W30 manifold and custom fit to the small block for all proper clearances.

They will fit 1964 to 1988 small block Oldsmobile 307, 330, 350, 403. Will fit all GM A body cars, G body cars, F body Trans Am with a 403 and 1971 and newer B and C body cars.

$299.00 for the set or $175.00 for one side


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