![]() By keeping more heat inside the header tubes, exhaust gas velocity is maintained, so the headers have better scavanging characteristics.įinally, make sure your cylinder heads have the end holes drilled and tapped for the header bolts - a lot of Pontiac heads do not have the holes for the end bolts, so you have to drill and tap them. The LS manifolds are still on the heavy side but they weld super easy and flow probably somewhere close to a set of shorty headers. They run cooler, keeping the heat in the tubes and out of your engine compartment. They stay looking nice much longer than painted headersĢ. The ceramic coated headers have a couple of advantages:ġ. Also be aware that any header on a GTO will reduce ground clearance a bit. There are cheaper ones available, but you may need to do a little grinding on the bolt holes and a little hammer work on the tubes to get them to fit. If price is not a problem, the Hooker SuperComp headers are top-notch. ![]() If you get bolts with heads bigger than 3/8", you won't be able to turn the bolts, and if you get 12-point bolts, you can't get an open ended wrench on them (which you have to do on the center bolts). Make sure you get a set of header bolts with 6-point 3/8" heads so you can get an open-ended wrench on them. The header flange bolts are difficult to get to due to the angle of the exhaust ports and the tight wrap that the header pipes have to make to miss the crossmember. Header installation on a Pontiac is not an enjoyable process. Tentative date is Late April 2023 Price: 489.95 Buy in monthly payments with Affirm on orders over 50. Headers are also longer than exhaust manifolds. Exhaust manifolds are made of thick iron, while headers are made of lighter, thinner steel. The cam you're using really needs some flow on the exhaust side, and any headers will achieve this. Description: Pontiac Ram Air D-Port Exhaust Manifolds for 1968-1972 GTO (A-Body), 70-81 Firebird (F-Body), 2.5' Outlet (Pair) (Requires 2- FL-1-OS / H-1 Hardware Kit) Item : RAR-RM-2-OS Not Available Currently not in production. The structural differences between exhaust manifolds and headers are the material and size. The Pontiac Ram Air manifolds are much better, but still not as good as tubular headers.įor a street car, the brand and tube length of the header is not that important - the key is to simply get the flow on the exhaust side. The stock Pontiac manifolds are actually quite restrictive. With that said.Headers are quite a bit more effective than the stock manifolds - about 15 horsepower on most tests I've done. I like to think that I'm trying to have my fun without totally disregarding the efforts to keep the air clean. Not that I'm a tree-hugger environmentalist or worried about my emissions warranty - but I like the idea of replacing the cat with a larger one instead of gutting it. Most likely the reason some of the intake and exhaust mods don't feel like they do much is because of the restriction the cat puts on the system. As the name describes, the difference between a UEL and EL header is the length of the exhaust piping: UEL headers has 1 side of the exhaust pipes longer than the other vs EL headers. the bottle-neck is most definately the stock cat. duner got 38hp from a high flow cat between 50 all that coudn't of been from just a 3 inch cat. manifold - Hey i noticed a pretty good sized crack between my 6 and 7 cylinder on my exhaust manifold. The 3.9L sounds like it has had the only REAL benefit.īut most of the people with headers still run a catalitic converter. So far, I haven't heard of any increases with just a JBA header change over stock (on 4.7, 5.2L, OR 5.9L). The stock 4.7 manifolds flow very well,just look at their swept back design,the headers will flow more on the top end and if you have a supercharger or turbo they would be worth it,these manifolds look better than the old 340 hp manifolds and Im sure they flow alot better too ![]() If you dont notice any power gain, its because you've done something wrong!Īlex is correct, a cast factory manifold is a chokehold on the exhaust. Hey Horbedarn, I dont understand why you wouldnt add more fuel to compensate for the headers you installed. Headers aren't going to be compatable with the Speedtweaks turbo - so keep em how they are ) MBRP Dual Exhaust Cat-Back, JBA Headers, 72mm TB, 4" Z-Tube Shop 1932 Ford E-350 Club Wagon Ford Flathead V8 Headers and Exhaust Manifolds and get Free Shipping on orders over 149 at Speedway Motors. If you want every little bit possible go ahead and do them but other wise it really isn't worth it. I put the JBA headers on and didn't notice any power gain. Headers are always better than manifolds. My rules say not center dumps so I am have no comparison to thoses. Weather or not they actually flow better I have not tested but I have to think if the volume is larger they should flow better. IF you see these manifolds you will be cvery surprised how large they look. I have read a few posts saying that the stock exhaust manifolds breath fairly well.is it not worth the money and install time to buy a set of headers for these 4.7's? If i should just get a cat-back than i would. The manifolds I run are off of a 87 V2500 chevy truck. ![]()
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