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#41
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Good thread going here.
It looks like Pypes sells two types of downpipes. One with the flanges (DS10S) and one without(DGA20S). The set without flanges are not necked-down and would have less restriction but it looks like they will only work with RA manifolds: http://www.pypesexhaust.com/downpipes.html I suppose we cannot get these for Logs because the sharper radius requires the flanges to be pre-installed. |
#42
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Did they replace with new ones with a larger bell? |
#43
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I just installed DS10S and DGU11 . They were not that tight of a fit. But I had to remove and reinstall them together for the correct geometry. They sound great. Manifolds wil quiet mufflers and tailpipes and it is still pretty loud outside of the car. Inside it is nice and quiet. A small amount if any of get-up from the start and no lose of top end with manifolds.
Granted I am less then 400 HP. I would recommend the Pypes numbers above and manifolds. Dave
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1967 Pontiac Tempest 2dr HRDTP Coupe 468 C.I. 500 HP 5 speed = FUN!!! 1990 Chevy Suburban R2500 Daily Driver 1986 Volvo DL245 Wagon.. Project car!!! The Burb Files |
#44
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unless you are doing a 100 point resto, id leave it out, and even if you do a 100 point resto, id tack weld it open.. i think opening up the log outlet and extrude hone polishing sure cant hurt..plus with good mandrel pipes that dont neck down you should be good up to 1hp/cu in.... Last edited by zeebo; 11-25-2012 at 12:26 AM. |
#45
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Yeah I tack welded mine open.
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1967 Pontiac Tempest 2dr HRDTP Coupe 468 C.I. 500 HP 5 speed = FUN!!! 1990 Chevy Suburban R2500 Daily Driver 1986 Volvo DL245 Wagon.. Project car!!! The Burb Files |
#46
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Removed mine and put a pipe plug in the holes.
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#47
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manifold
This is an excellent thread full of good info. My question is this, do the original
FB manilfols have a heat flapper in them. the reason I ask is because i don't recall mine having them when I removed them during resto 10 years ago. I just sandblasted them and coated them with exhaust calyx. I do plan to remove mine again and clean them ports up and resize exhaust exit hole. Gerry C
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1968 Firebird 400, 068 cam, TH400 & 13" Continental Converter, Auburn posi with 3:08 factory gears, Cliff's Q-jet resting on a 68 factory iron intake, DUI HEI and Ram Air pans and RARE Long Branch Manifolds |
#48
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Glad to see this thread.
Good tech, B-Man! |
#49
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#50
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Is the heat riser necessary with an automatic choke?
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#51
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Some years didn't have the flapper at all. So, no not necessary.
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1966 GTO 1969 Lemans Convertible- F.A.S.T. legal family cruiser. 12.59 on G70-14 Polyglas tires. 1.78 60' 1969 Bonneville Safari- cross country family cruiser. . 1979 Trans Am 400, 4-speed, 4 wheel disc. View from the drivers seat racing down Atco Raceway- http://www.youtube.com/watch?v=GhYDMdOEC7A Ride along in the other lane-http://www.youtube.com/watch?v=mIzgpLtF_uw |
#52
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Here's a pair of 1959 389 log manifolds.
Pontiac exhaust manifolds have a nice free-flowing design, much less restricted than the standard exhaust manifolds of most other makes. I'm particularly fond of the driver's side manifold with the center outlet, purely from an aesthetic standpoint. A pair of these would look great on a fenderless late '20s or early '30s roadster with an open engine compartment.
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1964 Tempest Coupe LS3/4L70E/3.42 1964 Le Mans Convertible 421 HO/TH350/2.56 2002 WS6 Convertible LS1/4L60E/3.23 |
#53
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It's funny that I still can't see any photos that are posted through photobucket. I see nothing in your post but the script Bart. The email alert shows links to the photos but when I click on them, "This site can't be reached".
Strange.
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Greg Reid Palmetto, Georgia |
#54
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Nevermind...I just realized that it's only my job's network that filters PB out. I just looked at the 'Post a photo that you took' thread and noticed that a couple of pics I viewed at home are not viewable here.
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Greg Reid Palmetto, Georgia |
#55
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Im curious why they cut out the center on one side and not the other.
__________________
1967 Pontiac Tempest 2dr HRDTP Coupe 468 C.I. 500 HP 5 speed = FUN!!! 1990 Chevy Suburban R2500 Daily Driver 1986 Volvo DL245 Wagon.. Project car!!! The Burb Files |
#56
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But wait! There's more! (there always is) Let's not forget about the exhaust crossover. When that flapper is closed, the passenger side's center is now the exit. Forget what I said about orderly. Everybody on that side is now trying to exit through the intake manifold. And you've seen the size of that exit. Can you say gridlock? Hey, let's knock out that wall! I'm sure that only scratched the surface, and I could even be wrong. |
#57
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I've got a 72 Lemans I've had for 30 years. It was my high school project. It's got a 400 bored 30 over, #16 heads, 068 cam, cast iron manifold with Q jet with dual snorkel, log manifolds and 2.25 crush bent exhaust with quiet mufflers. HO racing carb and distributor kits.
Running a fresh 200-4R transmission and 12 bolt 3.55 rear end. With my dragy my best 1/4 mile run is 14.59 at 96 mph. Thought it would be better. Always wanted to do the ram air manifolds but then I saw this post! How much performance gain would I get with the log manifolds opened up to 2" and a pypes 2.5" mandrel system? VS what I have now? VS ram air maniolds and pypes 2.5" mandrel system? Thanks! Kent Kelsey |
#58
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--------------------------- Fool Around, Get Hurt, Don't come Crying to me. |
#59
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Awesome thanks! Any opinion on what the ram air manifolds would add to that?
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#60
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maybe another 1/10-2/10 if they were port matched and polished? The big question is finding a pair. They are out of production now. The whole Pontiac industry has been out for a while. So they are really hard to find.
__________________
--------------------------- Fool Around, Get Hurt, Don't come Crying to me. |
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