I just wanted to share this news with Y-Blockers considering the "H" pipe in their exhaust.  The race truck was chassis dyno'ed without the H pipe, with H pipe, and with H pipe and 6" Flowmaster race mufflers.  Also the H pipe did quiet the exhaust a little before mufflers were installed.

Obviously this is not pure scientific research, but it did help me to decide what exhaust configuration to run.  As you can imagine, each and every engine with different cu. in., horsepower and muffler type will give varied results.

Here are my results at the rear wheels with pulls from 3000 to 7000 RPM:

Exhaust configuration     Max Horsepower (RPM)     Max Torque (RPM)

  No H pipe or mufflers               237 (6600)                     211 (4800)

  H pipe with mufflers                 247 (6800)                     216 (5000)

      H pipe only                         250 (6800)                     217 (5000)

For me it was a 5.5% increase in horsepower with the H pipe alone.  Torque is important, but the hp is what helps me push that air at the top end.  An increase in torque should give you a little better performance from stop light to stop light. When I told the dyno tech that the mufflers were by Flowmaster, he said he notices better increases with Dynomax???

When Tim McMaster finishes the new engine, we will dyno again using a new "X" pipe system with and without Dynomax mufflers.  Attached is a picture of the current exhaust system.  Existing crossmembers didn't allow for an H Pipe closer to the header. I've been told closer is better, but I did this on the road between Columbus 08 and Maxton with limited facilities.  The new X pipe system will be much closer to the collectors.  Also Tim has posted a video of the dyno pulls in the "Racing" section under "Flying Yellow Brick at Maxton".

Hope you enjoyed the report.

Charlie Burns Laton, Ca (South of Fresno)



BurnsRacing981@gmail.com