How long should the primaries be on Long Tube Headers? Well, the simple answer is not too short and not too long. Somewhere between 30-inches and maybe 33-inches seems to kind of be the standard. The funny thing is that if they are shorter than that it really doesn't seem to hurt power at all. The only thing about making the primaries shorter than that is that you can no longer call them Long Tube Headers. And so what? When we started building headers, there was no such thing as Long Tube Headers, they just called them "tubular headers". I can't actually remember when the name "Long Tube Headers" first started. Probably when the original Mustang 5.0 headers were introduced, and people started referring to them as "shorty headers". At any rate, Long Tube Headers is what people ask for and that's what we offer for the early Mustangs (1965-1971) as well as the later Mustangs (1979-1995). On the early Mustangs, depending on the year of the car and the deck height of the engine (8.2-inch or 9.5-inch), we offer Long Tube Headers with 1 5/8-inch up to 2-inch primaries, for pretty much any cylinder head you can think of. Are they equal length primaries? Nope. They are as close as we can get to being equal length considering the tight engine compartments, but they are not equal. Nobody can build equal length header to fit into stock chassis. The good news is that it really is not very critical if the primaries are equal length. It's a myth.
This is about as close aw we can get.
If we had all the room in the world under the hood of a Mustang to build headers like this, we could do it, but that is just not the case. Actually, these headers are probably not perfectly equal either. But again, so what? It really is just not that critical. And even if they were equal length, the length is only "perfect" for what RPM? 6000 RPM? 6800 RPM? 7500 RPM? 5000 RPM? Pick one because the "perfect" length is only "perfect for one specific RPM, and is either too short or two long for any other RPM. But, and this is a BIG but, we do not run our engine at only one RPM. We want good performance maybe starting at 3000 RPM all the way up to maybe 6500 RPM, and there is NO "perfect" length for an RPM spread like that. And so, we compromise. By the way, the same holds true for intake manifold runner length. It's not always easy to have equal runner length on intake manifolds, either, and even if we could, what is the "perfect" runner length? Same issue as with headers, there is no "perfect runner length" for all RPM's, only one specific RPM. In the 1970's, when the Can Am sports cars were a big deal, the McLaren's were the hot set up.
They were powered by fuel injected Big Block Chevy engines.
The runners are NOT equal length, on purpose. Sports Car racing engines are constantly going up and down on RPM, going into turns, coming out of turns, straight aways, etc., with the driver shifting up and down dozens of times every lap. The McLaren engineers figured out that the only way they could get the "perfect" runner length, was to compromise and make four runners too long and four runners too short, and somewhere in the middle was the "perfect" length.
Anyway, if you are looking for good fitting high performance headers at a fair price, give us a call at (909) 552-3690. Every header is built one at a time specifically for the customer's car / engine / transmission combination.
George Klass - RCI Custom Headers
This is about as close aw we can get.
If we had all the room in the world under the hood of a Mustang to build headers like this, we could do it, but that is just not the case. Actually, these headers are probably not perfectly equal either. But again, so what? It really is just not that critical. And even if they were equal length, the length is only "perfect" for what RPM? 6000 RPM? 6800 RPM? 7500 RPM? 5000 RPM? Pick one because the "perfect" length is only "perfect for one specific RPM, and is either too short or two long for any other RPM. But, and this is a BIG but, we do not run our engine at only one RPM. We want good performance maybe starting at 3000 RPM all the way up to maybe 6500 RPM, and there is NO "perfect" length for an RPM spread like that. And so, we compromise. By the way, the same holds true for intake manifold runner length. It's not always easy to have equal runner length on intake manifolds, either, and even if we could, what is the "perfect" runner length? Same issue as with headers, there is no "perfect runner length" for all RPM's, only one specific RPM. In the 1970's, when the Can Am sports cars were a big deal, the McLaren's were the hot set up.
They were powered by fuel injected Big Block Chevy engines.
The runners are NOT equal length, on purpose. Sports Car racing engines are constantly going up and down on RPM, going into turns, coming out of turns, straight aways, etc., with the driver shifting up and down dozens of times every lap. The McLaren engineers figured out that the only way they could get the "perfect" runner length, was to compromise and make four runners too long and four runners too short, and somewhere in the middle was the "perfect" length.
Anyway, if you are looking for good fitting high performance headers at a fair price, give us a call at (909) 552-3690. Every header is built one at a time specifically for the customer's car / engine / transmission combination.
George Klass - RCI Custom Headers