Is this a statement of results, or opinion? I find it hard to believe no difference would be noticed on a stroker going from cast manifolds to headers. On the dyno my 408 made 25 more horsepower going from 1 5/8 headers to 1 3/4 headers. I'm pretty certain 25 hp can be noticed, manifolds to headers likely a bigger gain.
Was the dyno run through mufflers, or open? On the street, the exhaust is bottled up so that would likely negate some gain. I don't mind installing the shorties if they will provide a notable gain, but is it worth the effort and need to go back to the exhaust shop to have them join the existing exhaust to the new headers? That is my question. Also, I am running the 1970 340 manifolds if that makes any difference.
Do the shorties even fit?
I did a test fit when I installed the engine, and yes they do.
Good point. The TTI headers have a coating that should reduce underhood temps as well.
Thanks for reply, I must say, I find these results surprising. This was a 408?
You are right, and I too have been there. The big difference here is these headers are the shorties. The long tube headers were the real pain for me. These headers have great plug access and should provide good clearance to the (mini) starter I have. I have done so many engines in the past that I do not recall specifics, but I used Hedman a lot back in those days. We have options today that were not available back then. For that I'm grateful!
I think this is a "do what makes the most sense for you" scenario. If you are only driving this on the street...can you feel the approximate 20 top end HP that shorty headers may gain vs manifolds? The engine will certainly breath better, but at the same time, if that takes you a weekend, and several hundred bucks in getting exhaust re-done...then thats your call. I'd make the same contemplation if it was worth the time and money. Now if we're talking manifolds to long tubes...yes I 100% believe THAT would be worth it. If you see any strip action, assuming you hook...I'd guess manifolds to long tubes may gain you a few tenths. manifolds to shorties...probably 1/2 of that gain, but also depends on how much the manifolds are choking it. I have never "bothered" putting shorties on anything in my life, and probably never would unless they were cheaper than a replacement manifold, and i had a cracked one or something. if you're going to the trouble to install headers, i'd go long tubes. Now if those are those TTI Tri-Y things...those are closer to a long tube than a shorty...so if you have them, i'd probably throw them on.
you're correct...most long tubes in an A-Body aren't much fun to install. Between the drag link going between the tubes...the low ground clearance...having to take the engine lose. But on the flip side, some of the $ versions that don't go through the drag link, cook the starter. It's a balancing act. Yay hotrodding
Thanks for the comments. Yes, now decisions, decisions....
The TTI shorties fit almost perfect, and will not leak. They make a nice, quality header. But you'll really need the TTI headpipes that go with them. Only place I had fitment issues was at the kickdown linkage on the transmission. It's pretty easy to modify, or just use a Lokar kit. I have no idea on the performance. I never had a chance to compare them to stock manifolds.
Thanks. I already have the Lokar kit installed. Only other deviation from stock is I plumbed the cooler lines with -6AN braided hose because the original lines were bad.
