Don Terrill’s Speed-Talk

We run a limited late model in an asphalt oval track car. 380 HP with a 2 barrel carb..
There is new rule change this year..We can run a howe 2 into 1 muffler this year.. with a maximum of 18 " long tail pipe with maximum OD of 5 "...we run a X pipe. Are these mufflers better or should we just run 2 small straight thru mufflers ?? Maximum 3 inch.pipe.thanks

Need more details on the engine.
What carb?? What Intake?? What Cylinder heads?? What headers are you running currently?? What collector size and length are they currently?? Where is the power band at?? What RPM do you come off corner at??This will determine what to do.
On restricted 2bbl engines a stepped header works better then a single larger tube header on a 2 into 1 system.
We found on limited 2bbl stuff 1 1/2 to 1 5/8 step with a 3" collector about 18"" gains 50HP and 50 Ft Lbs on some 2bbl sprint stuff we do over a single 1 3/4" tube size and larger 3 1/2" collector.
Also the Howe iron lung header system works very good on 2bbl stuff if you have not looked at them yet.

Personal opinion: if the muffler and tailpipe are a restriction such that the back pressure is too high, moving the mufflers as far downstream as possible would make sense.

tried them on 500 2 barrell 350 sbc around 400 hp and tq did nothing. guy liked the sound of them so he ran them. one night he noticed muffler was falling off so he pulled it off and just ran headers alone. he said it felt like a 25 hp gain. i dont remember pipe diameter or collector but he never ran the iron lung muffler again.