383 Exhaust Manifiolds vs. Headers
The guys that are recommending that the OP utilize the OEM big block A-body
exhaust manifolds are full of beans.
Perhaps the VERY WORST stock manifold out there is the pinched down LH side
manifold that exists for this application only and singlehandedly costs you at least
30 horsepower.
A company called Accurate LTD was making a modified LF side manifold to directly
address this concern. I don't know if they are still available but if they don't have
them on the shelf, perhaps they could make you one. the difference is obvious.
Comparison photo below.
Accurate LTD LH Manifold web site: ....... http://69gts383.com/New_left_side_manifold.html
The guys that are recommending that the OP utilize the OEM big block A-body
exhaust manifolds are full of beans.
Perhaps the VERY WORST stock manifold out there is the pinched down LH side
manifold that exists for this application only and singlehandedly costs you at least
30 horsepower.
A company called Accurate LTD was making a modified LF side manifold to directly
address this concern. I don't know if they are still available but if they don't have
them on the shelf, perhaps they could make you one. the difference is obvious.
Comparison photo below.
Accurate LTD LH Manifold web site: ....... http://69gts383.com/New_left_side_manifold.html