Header Size

...From the book 'Ford Performance' by Pat Ganahl: For the 351 Cleveland. For Drags and Circle Track; Primaries at 2 1/4" O.D.(2.0" I.D.) 34" Long, with the Collector at 3 1/2" O.D to 4 1/2" O.D... For STREET Use: Primaries at 1 3/4" to 2.0" O.D. 40 Inches Long, NO Collector size Mentioned! Go with 3.0" to 3 1/2" O.D...

Thanks for the info. Its a great help.
Mark

Mark,
Check this out,
http://www.strokerengine.com/Headers.html
I,m thinking the CC Inserts on straight pipes!


Mark

You don't have a lot of choices in headers. The biggest problem with Pantera headers is the lack of a proper collector. Too many Pantera headers were manufactured to mate with the OEM tailpipes, which are far too small in diameter. Any header designed to mate with the OEM tailpipes are not worth the money.

It sounds like you already have the GTS exhaust system, which is a good compromise between price, drivability, performance improvement, noise level and ease of installation.

The best header available from the standpoint of craftsmanship and collector design is Pat Mical's header. In my opinion the next step up in improving your exhaust system will be Pat Mical's headers mated with your GTS tailpipes. Adams Hudson is running just such an exhaust system, you may want to contact him for his thoughts.

Whether or not you need a larger diameter tailpipe and better muffler depends upon the state of tune of your motor. A 400 BHP motor does not need the larger tail pipe system, a 500 BHP motor could use it, but I would also point out that David Berman's 408 cubic inch motor with Blue Thunder heads & roller cam is making 540 BHP exhausting through a stock GTS exhaust system.

Quite often a low back pressure tail pipe & muffler system will give the motor a harder "hit" when it comes on the cam, and make more noise, but not really increase torque. The harder hit is caused by a dip in the torque curve between 2000 and 3000 rpm resulting from the increased size & lower back pressure of the "larger" tail pipe system. In my opinion a hard hitting powerband like that is detrimental to drivability.

cowboy from hell

The Cleveland series heads, 2-1/8" tubing is about right. Remember we are talking tubing and the difference between tubing dimensions and pippe dimensions is that tubing dimension is the OD and pipe is the ID.

Racers like to acid dip the headers in the pro series in order to make it as thin as possible. Thin headers to them are "good headers". The thick tubing you would want for durability on the street would be "bad tubing" to a drag racer.

If you listen to the harmonics of the big tube headers on a Boss 302 at distance the tone is lower, more bass, then the Windsors.

I think that is bad. It is showing me that power is being lost through the system.

2-1/8 is too big for them. 2" is about right.

On a Cleveland 2" on the street is about right with a 3-1/2" collector. The problem is getting the pipe lengths correct.

The only way I can see all of the exhaust tuning size vs. length working in the Pantera is with a 180 system. Then that system tends to get restrictive over a certain rpm range. Certainly it's done at 8000 rpm while a big tube normal set of headers is still going.

What am I saying? I don't know? Do you know of anyone that can harmonically tune a big Church organ? Introduce him to a header builder. At least if it doesn't make power it will sound good! Tell them you want to make the car sound like an Indy car or one of those "crazy bikes" that crank out 14,000rpm. No wait...don't do that. I did and those guys got together and beat the crap our of me. Don't go that way.

Dam. Now were back to square one. I must need more coffee or another Martini or something. Gobble, gobble. Later...

Since my earlier post I have purchased a set of 180's to be used on my track car. I don't know about the CC inserts. Looks like more restriction to me. I hope to run straight pipes on the track and glass packs on the road.
Mark

I have Halls 180's. Bob from Precision Proformance makes them. They use 18" 2-1/2"ID glass packs. The primaries are 2" and they were made for my A3 Motorsport heads.

The mufflers are loud at full throttle. Kinda civilized on the street...sort of.

I am kind of surprized that no one is using step tube design. I know for a fact that they are very effective in the vintage road race cars and all of the front runners are using them.

The front runners are also making 650hp out of a 289. Step tubes under those conditions have to be a considerable difference.