340 HP's vs headers

dustoff440 said
I was in the same sit as you with a warmed over 360 MAgnum, Dyno tests have shown 20-25 horsepower where headers are put on a pretty much stock 340 the better headers (tti) had about 5 horsepower over cheaper ones. Your 318 build will not garner as much horsepower as the 340. The stock 340 manifolds 68-71 will give 11 horsepower over 318 manifolds. With 20 xtra horsepower you are not going to set the world on fire. 20 hp is only 2/10 in the 1/4 mile. If you already have a set of manifolds I would say run them, if not spend 150 bucks and get the Summitt headers.

http://www.forabodiesonly.com/mopar/archive/index.php/t-12000.html

http://www.moparts.org/Tech/Archive/exhaust/9.html

http://www.moparchat.com/forums/archive/index.php?t-76417.html

These are great threads & the 2nd one has several folks indicating that the large tubes (1 5/8") & collectors (3") would actual hurt torque in a setup like mine which will probably make just short of 300hp. Am I reading that correctly? That ideally a mild setup like the one I'm building would only properly benefit from 1 1/2" tubes & 2 1/4" collector? Even the Hedman shorty headers referenced above still have a 2 1/2" collector & still use 1 5/8" tubes. Folks from that thread compare the shorty headers to the 340 manifolds would any of you guys see things the same way as described there & if so, is that telling me to either have custom headers built (which Im sure is not in my budget) or go shorty or manifold? I dont want to make a poor decision based upon my modest goals.

PAR/T said
I speak from years of experiance when I say this, especially when dealing with A-bodies...Headers are not worth the trouble for that level of performance. For 300 hp you'll be much happier with the 340 manifolds. If in the future your shooting for 375-400 hp, I would consider swapping in the headers.

What are your thoughts on the shorties as they seem to run just a little cheaper? Similar pro's & cons to the 340's in your opinion?