Exhaust Pros/Cons for Slant 6
Get ready for things to go off track, whenever anyone mentions UTG, it turns into a hate thread rather than a help thread...
It doesn't have to be that way. Uncle Tony is full of ѕhіt on this and many other points, so it's a good and helpful thing to warn people who don't know any better off of following his advice, but it really doesn't need to go any further along that road.
Thoughtfully-configured dual exhaust—according to people who actually know what they're talking about, from Chrysler's own engineers to Doug Dutra—brings real, solid, practical benefits in usable performance on a Slant-6 engine. You don't want to overdo it with too-big pipe diameters, and duals all the way back is past the point of diminished returns for many street builds (unless the point is to listen to the pipes), but a recipe like
this is good. The Dutra Duals are now made in Australia, and the preferable setup for street use is Doug's original configuration: a Dutra front-3 unit with a cut/capped rear half of a stock exhaust manifold (keeping the central collector area for intake heat, and the automatic choke tower).
But a 2-1/4" headpipe coming off a stock exhaust manifold (the outlet can be enlarged a bit) into that same muffler and resonator as linked above is still a nice and much less expensive upgrade over stock miniature pipes.
