Here are the dyno results on some exhaust testing performed on a +060 over 272 Y that had stock 1956 ECZ-C heads, 1957 ECZ-B 4V intake, an Isky E4 camshaft cut on 112° lobe centers, and a Carter 600 cfm carburetor sitting atop a ½” phenolic four hole spacer.  This test compares engine performance with a set of long tube headers against a set of rams horns exhaust manifolds.  The headers used are the EMC (Engine Masters Challenge) headers which are a 1.75”/1.875” stepped header with mufflers.  The ram horns manifolds were hooked up to ~5’ of 2½” diameter exhaust piping with no mufflers on the ends.  Also had the opportunity to test with and without the air cleaner for both exhaust tests so here are the graphs for each scenario.

From a scoring standpoint and without the air cleaner on the engine, the EMC headers with mufflers scored 1564.8 points while the rams horns manifolds and open pipes scored 1547.6.  Scoring with the air cleaner in place had the EMC headers at 1536.3 points while the rams horns manifolds scored 1500.5 pts.

Lorena, Texas (South of Waco)