Small block exhaust

[Milkmann]

I want to re-do my 74 Challenger exhaust, P.O. installed a solid valance panel in the rear with turndown exhaust pipes. I have ordered a valance with cutouts, and am going to go with stock-appearing tips. 2 questions, 1) where is the best deal to be found on tips that have a stock outward appearance? I kinda like the all-stainless ones on Ebay, they come it different inlet sizes.

Second part of question-I have a basically stock 1968-spec 340, am I going to get a significant noticeable performance gain from headers and fat exhaust pipes? Engine already has the cool hi-rise exhaust manifolds. I wanted to go with 2-1/2 or 3 inch exhaust, but if it's already choked down at the manifold outlet that wouldn't do any good, would it?

[Super Blue 72]

You can find some good deals on Ebay but I remember one member here got some from Pypes and it had the Pypes logo etched on it, on the top, so it was visible when installed. That might not to be to your liking, just an FYI.  I think he got them for very reasonable $, I want to say something like $150 or so?

As far as "fat" exhaust, too much is not always a good thing.  Others more expperienced than I will probably chime in but I wouldn't go more than 2.5 inch on a slightly hopped up 340.  Too much exhaust savenging is not good.  Headers will give some performance results but it all depends if you want the stock look or not, sometimes people say that headers have to be tightened every so often... 

[Aussie Challenger]

I agree with Super Blue 72 about going too large on the pipes, if you are going with headers get decent ones which means a few extra $$$ but the fit will be better, TTi have about the best and they also sell exhaust tips. Have a "X" pipe installed as well. If you do decide to modify the motor some more down the track then the exhaust will all be in place to compliment those upgrades. Do it once, do it right.   

[72cudamaan]

I don't see you having any gain by going to a 3" exhaust. A set of full flow mufflers and mandrel bent pipes would definitely give you a nice gain in power. There is such a thing as " too much".

[mopar12372]

2 .50  max for small block .

[Chryco Psycho]

 .
2.5" with TTI or Dougs headers with an X pipe  , the larger exhaust will help even after leaving the smaller manifolds
TTI also has stainless tips in different pipe sizes to match the exhaust

[Road_Runner]

I've got a set of the AAR/TA style exhaust manifolds that I'm strongly leaning towards for my small block Barracuda.  Its got the standard 318 exhaust manifolds and a decent 2.5" dual exhaust right now and I definitely don't think those are choking the mild 318.  If I hop up the 318 or swap in a 340 I'd definitely go with the better TA exhaust instead.  So on your mild 340 I'd probably stay with your manifolds as well.

Later, Jim

[mopar12372]

have you ever thought of extrude honeng the exhaust manifolds? http://www.extrudehone.com/auto/auto-performance.php

[Aussie Challenger]

have you ever thought of extrude honeng the exhaust manifolds? http://www.extrudehone.com/auto/auto-performance.php

I wouldn't bother, dollar for power increase would be a waste.