Why does everyone say that a good set of headers and exhaust pipes will flow better than the sidepipes?

Is it because they have such long primary tubes? Or is it all the extra bends to direct it out to the side? Or is it the crappy mufflers that come with the sidepipes?

 

The mufflers in side pipes really cut the flow. Here's an excerp from Spiral Turbo Specialties site:
Testing done by: Romar Enterprises, Walden,NY
Car: 1969 Corvette Engine: GM 502BB, Iron rectangular port heads, hydraulic cam/220 duration@.050 and .500 lift, 8.75 to 1 compression, low rise LS6 intake, holley 750 double pumper carb, and Hooker Sidepipe Headers. Tests are RWHP figures 1/5/2002
Base: Mufflers, HH reverse flows. 246.7 HP/388.9 torque.
2nd pull: Mufflers/ baffles, Spiral Turbo Baffles (4"). 338.5HP/408.8 torque. An increase of 92HP and 20Lbs. Ft. of torque.
3rd test: Sidepipes, no mufflers or baffles. Wide open tubes. 342.4HP/445.1 torque. Thats a high bolt on increase.
This particular engine needs more cam and head work, suggested by Romar, Ent. after testing was complete. Romar felt with these modifications, getting power in the 550+ range would not be difficult.
These tests are indications what can be achieved by using Spiral Turbo Baffles. Your results will differ depending on the engine, and the amount of modifications. This 502 is basicly a stock engine. If you have more questions about the tests results, get in touch with Kenny, at Romar Enterprises 1-845-778-2737, or Spiralturbobaffles.com

90+ Hp difference between mufflers and spiral baffles, that you'll be able to feel :yesnod:
Scott

 

With the 69-style factory sidepipes, they are definitely correct since they are very restrictive. With the Hooker sidemounts, I'm not so sure. Possibly the only reason is that you can't put an H or X-pipe in the Hooker sidemounts. Otherwise, since many who are using the Hookers have big blocks with alot of HP that must breathe, I think they are the only way to go for big HP engines since they have 2 1/8" primaries into a 4" collector for max flow. It is correct that you should stay away from the inserts that Hooker sells and go with the JCL inserts for highest efficiency. I don't think you can put regular headers with 2 1/8" primaries under the car without ground clearance issues (this has been tried!). This may not be an issue for most small blocks which will be fine with smaller primaries since they aren't moving as much exhaust as a big block. This is all my .02, so please - no flaming. :cheers:

 

I just want to know the suggested procedure for putting my rocker covers back in place as well as the hooker side pipes? :crazy:

 

Although I haven't personally done it, I've looked into this and read that in most cases the rocker panels have to be trimmed in front where the pipes exit from under the car just behind the front wheelwells. I'm waiting for my buddie to take the pipes off of his car and then I will have them coated and put them on. I'm considering buying some used rocker panels that have already been cut or are damaged and use them instead of messing up my expensive-to-replace 69 ones. :eek:

 

I had to "notch" the fiberglass and rocker on the passenger side, the drivers side didn't need it. After sliding sidepipe on to collector(with anti-sieze) and bolting into place, slide rocker down and in behind it and screw it down.
Scott

 

I think it is the Hooker mufflers. Look back on Corvette racing, you'll see many race cars with similar headers/sidepipes to the Hookers. I don't believe they did it for the "look".

 

I have the baffles in my sidepipes but haven't got my motor back in yet. However, I solved the rocker panel problem by buying the painted black headers/sidepipes then bending the mounting tabs on the sidepipes so that they would mount under the car to the frame, there shouldn't be any need to remove part of the rocker or fiberglass where they exit from under the car. The rear tab works with the mounting hardware no problem, there is a hole in the frame in the correct location(at least on 81's), the front tab I drilled a hole for.

Here's a couple pics of them after I got them recoated, you can see how the tabs were bent and when they are mounted you don't see them unless you lok for them.

http://www.c3sharktank.com/scott/baffle1.jpg
http://www.c3sharktank.com/scott/baffle2.jpg
http://www.c3sharktank.com/scott/baffle3.jpg

 

Mark hit the nail on the head with everything. that was my car that was tested and it is those crappy Hooker mufflers. I also tried the 2 and 1/8 inch primary undercar headers and you have no ground or even worse floorboard clearance, at least on my car. So in my mind you could make the same horsepower with a well designed undercar system which I think Norval has but it is much easier I think with the sidepipes and the JCL baffles. Also the benefits of less cabin heat, easier to work on the car and no ground clearance issues.

 

(He really isn't that stupid ;)

Chuck

 

I resent that Chuck, how do you know if I am not that stupid. Oh by the way Chuck, what did you decide on for a cam? Is that roller in your future?

 

Marks...
The area that is cut out isn't all that big. I've had Hookers on my car for several decades now and I wouldn't ever go back to the regular exhaust. The sidepipes make the car and sound of a big block winding out is why I own a Corvette.