Hey DartGame,
Did you order the correct part # ?
Here's TTI's full description for Shorty headers for A-Bodies with a 383 /400.
I sure hope its correct info as I'm planning on using them myself for a 68 Cuda droptop project.
Header #44025
1-3/4" SHORTY HEADERS
Click image to enlarge
FEATURES ...
Designed for: 383-400 B-engines & 440 RB-engines
Primary tube size: 1-3/4" O.D.
Collector size: 2-1/2" with 2-1/2" 3-bolt flange
Flanges: 3/8" thick, laser-cut, contoured for a leak free fit
Material: Constructed of 16 gauge mild steel tubing. Mandrel bent on sophisticated computer controlled bending machines for precise fit and uninterrupted exhaust flow. The mandrel bending process maintains a constant inside diameter of the tube for a smoother finish with no restriction of flow and no crimping of the tubes.
One piece design: One piece header tubes / No slip tubes
Under chassis design: Above the steering center link design offers maximum header to ground clearance
Shorty header design: 2-1/2" Header Adapter Pipes required to transition Exhaust systems to headers
Recommended for: Up to 475 horsepower
Header set includes: Header gaskets & header bolts
latforms:
67-76 A-BODY, 66-74 B-BODY and 70-74 E-BODY CHASSIS.
[Check your engine location: See
FN39 for the factory dimensions]