Pure stock 340 Mopar

[Todd Boyer]

Originally Posted by Chipper Chapman

Todd, what A56 is talking about for the exhaust is that it's not the back pressure the system gives to the engine, but the velocity at which the exhaust gases have to travel in a smaller primary tube. The higher velocity (or rate of speed) will help to draw (or scavenge) the air/fuel into the cylinder during that minimal overlap period, effectively cheating the engine into thinking it has more cam duration. On the monte we ran small primary street headers (cheapo flowtechs) that achevied this, but with a 3" system and mufflers to not create excess back pressure. It went .4 under with a 100k mile engine.

Thanks Chipper, I'm beginning to figure this all out. You want velocity, but not back pressure. Did you use an X-pipe or H-pipe with your 3" system ? What class were you running ?