Here are the dyno results where several sets of headers are tested on a 314” Y.  Engine particulars include a 3.810” bore (+060 over 292 block), 312 crank with turned down mains, C2AE truck rods, ported ‘G’ heads, 12½:1 compression ratio with Dykes rings in the top lands, extrude honed Blue Thunder aluminum 4V intake, Isky 505-T cam with 254° @ 0.050” duration ground on 108° lobe centers and installed at 106° intake lobe centerline (2° advance), 1.6:1 Dove rockers, and a 830cfm Holley vacuum secondary carburetor sitting atop a 2” HiFlo spacer.  Engine performance comparisons are made in the 2500-6800 rpm range.

Here are some specifics on the headers involved in this test.

1. EMC headers – 1.750” X 1.875” stepped tubes with 3” merge collectors.
2. Chrome drag car chassis headers – 1.750” tubes with 3½” collectors.  Tested with 6” long 3½” diameter collector extensions and also with 27” long 3½” diameter collector extensions.
3. Upswept dragster headers – 2” tubes with 3½” collectors
4. Sanderson truck headers – 1½” diameter short length tubes with 2.375” collector openings.
5. Fenderwell headers – Circle Track specials, 1.750” diameter & long tubes with 4” collectors.
6. Fenderwell headers – Drag car specials, 1.625” diameter & long tubes with 3” collectors.

To keep the graphs from being too busy, they are broken down as two sets with the Sanderson headers being common on both graphs for comparison purposes.

Scoring is calculated from the 2800 thru 6800 rpms range and is as follows:

Sanderson truck headers, 1½” tubes, 2.375” collectors    - 1718 pts.

EMC headers w/o mufflers (stepped tubes, 3” collector   – 1715 pts.

Upswept dragster headers w/2” tubes, 3½” collectors    –  1702 pts.

Chrome drag car chassis headers w/27” extension        –   1700 pts.

Fenderwell headers w/1.625” tubes, 3” collectors       –    1692 pts.

Chrome drag car chassis headers w/6” extension      –      1690 pts.

Fenderwell headers w/2” tubes, 4” collectors          –       1679 pts.

Lorena, Texas (South of Waco)