Yep they sure are if you like replacing blown gaskets all the time , header bolts that loosen up, clearance and heat soak problems with starters, oil filter clearance issues. having to snake most brands around the steering centerlinks, cooked idler arms, problems with spark plug wires melting, and having problems with spark plug installation clearance issues, rusted out tubular pipes, collectors bottoming out, Yep definitely fpipesar better if you love these issues LOL
I have had headers before i f##king hate them. I just got a set of the 68 to 70 hi hi Po A body exhaust manifolds. The right side is similar to a header and they have large outlets. These are designed for flow.
The article from tti was with 78 dodge truck stock exhaust manifolds, with 2"exits. They may be from a LRT, but are a common as dirt stock 318 /360 pickup truck exhaust manifold. Id like to see a set of those numbers with a stock set of 68 A body hi po manifolds. But since tti did the testing, to arguably make their product look better, why not use the most restrictive stock exhaust manifolds you can find, and make the numbers look as good as you can compared to stock.
Im sure the tti pipes will flow better than a set of stock A body 340 manifolds, but how much more is the question? For me i prefer no blown gaskets, loosening bolts, hard to get to spark plugs, problems with pipes hitting my starter, or having to use a mini starter just so i dont end up with heat soak and a car that wont start when the headers toast the starter, as well as the idler link bearing cooking out from the heat.
I will take my chances with a bit less hp on my stroker 318 and run stock 70 A body hi po manifolds, and not have any of these headches. I believe the person who started this thread was asking about flow of the A body hi po manifolds not restrictive LRT manifolds. I know headers flow more but are they really worth the hassles i mentioned?