Here are the dyno results where three different header designs were tested on a +060 over 292 Y that has stock (unported) 1957 ECZ-G heads, 1957 ECZ-B 4V intake, an Isky 228°/238° @ 0.050” camshaft  with 110° lobe centers, 1.43:1 rockers, and a Ford 1.08” (440 cfm) 4V carburetor.  Engine performance comparisons are made in the 2500-5500 rpm range.  The EMC headers are a 1.75”/1.875” stepped header with mufflers.  The Reds headers have 1½” diameter tubes and are the pickup/truck headers (intermediate length tubes).  The Tri-Y headers are firing order specific for the Y and have 1.625” primary tubes.  Only the EMC headers were run with mufflers in place; just didn’t have mufflers for the other sized pipes.

Scoring is calculated by adding the average torque and horsepower values for the 2500 to 6500 rpm pulls, multiplying by 1000 and dividing by the cubic inch of the engine.  The scores are as follows:

EMC headers  1628pts

Reds headers   1623pts

Tri-Y headers  1607pts

I’ll add that the flattened out torque curve exhibited by the Tri-Y headers is similar to what has been seen with Tri-Y headers on other engines that used them.

Lorena, Texas (South of Waco)