I am in the pre-stages of piecing together my future exhaust system for my 78 and would like opinions on it. I am not very big on exhaust and I might be looking at items I dont need.

First off I will list the future engine rebuild specs that will acompany the exhaust.

CID 351W
Heads : Ford 1.94"/1.60" valves 60cc
Compression 9.1:1
Camshaft : 206*/212* 0.461"/0.474" 110 LSA Hyd Flat Tappet (600 - 4800 rpm)
Carb : Holley 600cfm 4V Vac Secondary with Edelbrock 4V EGR Valve Spacer plate
Manifold : Edelbrock performer dual plane manifold (idle to 5500 rpm)
Dist : OEM Motorcraft Dura Spark II
Coil : MSD Blaster 2F - High Performance Ford Coil

The CamQuest6 program that helped me deside on the camshaft I picked above is estimating atleast 320hp and 430trq, based off this and the chart I found on MagnaFlow`s website I desided on a 2 1/2" exhaust system (stock is single 2 1/4", 2 1/4" is listed for 150 - 250 cid and 100 - 200 hp)

But now onto the exhaust system this is what I have picked out so far

Headers : Hooker super competition headers full length - 1 5/8" primaries & 3" collector
Exhaust pipes : 3" to 2 1/2" header collector welded to a 2 1/2" exhaust dump further connected to a 2 1/2" H pipe
Mufflers : unsure yet I have been looking at performance oem styled cases as well as going back with the thrush glasspack I currently have
Tailpipes : stock style in 2 1/2" dual with GTO style stainless steel exhaust tips.

I dont know how good of a layout the above would be but that is what I am thinking. 2 1/2" is listed on MagnaFlow`s website as being for 350 - 400 cid and good for 250 - 550 hp.

On the mufflers I am unsure the ones I am thinking about are as follows

1. Hush Thrush Super Turbo (dont know what they sound like)
2. Thrush Welded (2 chamber style)
3. Thrush Glasspack

I thought about flowmaster but everyone I hear calls them chokemaster or some other name implying they arent any good. Plus theres the common complaint of annoying drone at highway speeds. If anyone would like to make a suggestion for mufflers the kind of exhaust sound I want is noticeable performance sound but not something that will get ever ricer wanting to race me when I am idling or just cruising along, but I would like an exhaust that gets loud and has a deep performance tone when I get on the throttle.

Other than that as far as to what I am unsure about getting it would be the headers and the exhaust dumps. The camshaft is a smooth idle but with the dumps open I dont know if it would sound good with headers. Then the headers I dont know if they are me just pissing away $700 for something that isnt much better than the stock exhaust manifolds. I will say I do need low rpm trq being the car is 4,000 lbs with a 2.50:1 axle ratio stock. So if anyone has any suggestions on the exhaust system as I have laid out I would greatly appreciate it.

 

The muffler for you is the WickledFlow 13SC250. That will sound perfect on that. It would not drone, but it will still sound snappy when you get on it.

The headers are a good idea. They will give you noticeable performance across the powerband. It would be better if the primaries went directly to a 2 1/2" collector, but I'm not sure thats even available and if it is, they would probably cost a lot more than what you've picked.

Overall I think you've picked a pretty good set of parts. But super turbos are not very free flowing, marginally better than OE mufflers. Glasspacks will be far too loud by your definitions, and the two chamber muffler will be in the same league as a slowmaster. The WickedFlow muffler in contrast is a straight through muffler with mandrel formed inner tube. It is similar to other straight though mufflers with the exception that it is built without any compromise. It uses tougher thicker steel, the packing material is higher quality, which has the added effect of making it quieter than most other mufflers, and it is just overall made much tougher than just about anything else out there at any price. I think you will like it much better than any of the Thrush mufflers.

Item Details

 

You're right I cant get headers that goes to 2 1/2" collector, there have only been two headers I found for my application and even then they are listed for a 78 Thunderbird, but considering the fact the Cougar and Thunderbird were pretty much identical in 77 - 79 and shared alot of the same parts I figured the headers would fit mine for sure. But the two that I found are a black painted steel one for $450 or ceramic coated steel ones for $800.

I desided on the painted ones cause I dont think spending $800 would see me any more gains performance wise over the cheaper painted steel ones.

I have photos of the headers though

Painted


Ceramic Coated




On the mufflers, I wasnt sure about the Hush Thrush Super Turbo they dont even have a sound clip for me to get a feeling of how they sound. Only ones I know how they sound is the Thrush Welded 2 chamber and the Thrush Glasspack which I currently have on the car and it sounds how I described. Problem is though the exhaust isnt loud without a muffler due to the dual converters that will be removed for the new true dual system. So they probably would be too loud and I am not that fond of the popping sound they make when you rev and let off the throttle. I will how ever check out the wicked flow mufflers though see if summit carries them then I can add them to my list. Only thing left after that is finding mandrel bent 2 1/2" exhaust tubing so I can piece the system together myself.



On the exhaust tips this is what they look like, I think they would go nicely with the car considering the car is somewhat styled like a transam of 77 - 79 with the longish hood and passenger cabin pretty much over the rear wheels with a very short rear deck/trunk. I dont know if they would help with exhaust flow or not but they were picked for looks more than anything, dont want exhaust turn downs that are hidden, it would also throw the sound to the ground and make the exhaust quieter than if they were pointed out the back or the sides.

 

Yeah, ceramic coated is better, but when you stop and think about it, stock cast manifolds might have surface rust, but have you ever seen one rot out? A good think mild steel will still last a long time even without the ceramic coating.

 

That is what I was thinking. Painted steel should be good enough their basically the same headers, and yea the painted ones will probably flake off and rust but it wont make the headers work any different.

Now I did hear some people talking bout the ceramic coating is good for pulling heat away from the heads but I wouldnt know about that. If I take and weld up a "heat shield" to plug in the stock aircleaner heat riser tube to I might strip the black paint off and have a local shop powder coat them then, eastwood sells some silver, cast iron grey, black exhaust powder coating powder.

 

On the net, please read:

broaderperformance.com/muffler_flow_tests.htm (Independently tested cfm flows of the more popular mufflers, glasspacks and resonators.



I have listed here a muffler shootout test done by CAR CRAFT:

The Mufflers
MAKE MODEL Part No. COST
SUMMIT Turbo 630125 $14.75
THRUSH Magnum Glasspack 24214 $16.50
THRUSH Boss Turbo 17718 $23.95
HOOKER Competition 21006 $25.95
DYNOMAX Super Turbo 17733 $28.50
DYNOMAX Race Magnum 24215 $31.95
HOOKER Super Competition 21106 $35.95
SUMMIT Fully Welded 630325 $38.69
FLOWTECH Afterburner 50322 $39.95

MUFFLER FLOW TEST

MUFFLER Flow at 28-in H20
DynoMax Race Magnum 528.64 cfm
Thrush Magnum Glasspack 507.40 cfm
Summit Fully Welded 343.38 cfm
Flowtech Afterburner 342.20 cfm
DynoMax Super Turbo 333.94 cfm
Hooker Competition 232.46 cfm
Hooker Super Competition 320.96 cfm
Summit Turbo 331.16 cfm
Thrush Boss Turbo 297.36 cfm

MUFFLER Idle dB WOT dB
DynoMax Super Turbo 89 123
DynoMax Race Magnum 94 133
Flowtech Afterburner 92 124
Hooker Competion 92 122
Hooker Super Competion 90 125
Summit Turbo 89 124
Summit Fully Welded 92 125
Thrush Boss Turbo 90 123
Thrush Magnum Glasspack 92 128

DYNO TEST
All mufflers were dyno-tested on a 355-cube SBC with 10.0:1 compression, Air Flow Research 190 aluminum heads, a CompCams 292 hyd. a Victor Jr. intake, a Holley 750-cfm double-pumper, and 1 5/8 Headman headers.


MUFFLER HP TORQUE 2,500-6,000rpmAverage
Hooker Competition 397.4 381.1 286.8hp/351.9 lb-ft
Thrush Boss Turbo 407.1 384.9 292.1 hp/357.5 lb-ft
DynoMax Race Magnum 409.5 394.3 298.8 hp/366.9 lb-ft
Flowtech Afterburner 409.7 391.2 294.8 hp/361.7 lb-ft
Thrush Glasspack 409.5 389.8 297.7 hp/365.3 lb-ft
Summit Turbo 411.5 386.3 291.5 hp/357.4 lb-ft
DynoMax Super Turbo 412.7 387.2 292.6 hp/358.6 lb-ft
Hooker Super Comp 413.8 387.2 292.8 hp/359.0 lb-ft
Summit Fully Welded 415.4 390.7 295.6 hp/362.4 lb-ft

 

The WickedFlow is gonna match the DynoMax Race Magnum in terms of flow and performance. However it will have a tamer sound than the Dynomax.