Quote:
Originally Posted by madmaxx
Greg,
You have figured the roush 427 better than anyone. Can you list your suppliers for the headers and sidepipes you used. If the muffler in the side pipe was exchangeble which one did you use?
Thanks
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I'm not sure if I figured anything out other than more air through the engine allows for more fuel to make power. Air is the tricky part. Fuel is simple.
Quite honestly I would be skeptical of my headers being anything special other than they were larger to not block part of the exhaust port and that I matched the gasket to the head so there wouldn't be material blocking flow. I think the headers I had were Superformance big block headers re-flanged to fit a small block. They were from the Olthoffs
www.olthoffracing.com The headers were about a 10 wheel HP increase.
The side pipes I used were from Buckshot Racefab.
www.buckshotracefab.net The 3 inch core had the louvers facing forward as I recall and the collector was a basic unit which had internal fabrication at the merge point. The side pipes I had did not have the same collector as what is currently displayed on the web page above the video of my car. I'm not sure of the science behind the intent with either version of the side pipes, but the side pipes I had were about a 25 HP gain and it made a wider torque curve. The change was notable for acceleration as the power gain was not only at top, but all over.
The mechanical secondary carburetor was from
www.pro-systems.com I'll just tell you right off this is the most notable power gain of anything. It made about 30 more wheel HP and made the car a pleasure to drive with instant throttle response and was extremely linear and could move the car along the freeway at 1800 rpm in 5th gear no problem.
Then there was the increased size air filter, fuel line upsized to 8AN from fuel tank pick up to carb, fuel filter replaced to large 100 micron Aeromotive, and rev limit increased for use of a bit more top end. All that was good for about another 10 wheel HP.
I also changed to stronger half shafts because one broke inside the 8.8 ford rear. I replaced the limited slip with a Detroit TruTrac and kept a 3.73 rear gear. I also went to a light weight McLeod flywheel and a stronger SPEC stage 3 clutch.
Mickey Thompson ET street drag radials in a 275/60 15 are the best modification I did to make the car fun to drive.
Other than all that I'd like to see an image of the new Superformance 402 header and be curious to know what size primary they have.
It would be interesting also to see some of the cars trap speeds which had side pipe change. Trap speed tells the real story of power if you know the DA too.
My thought about marketed HP gains is at times they may be exagerated.