Dr L-88

I went to put my new Hedman headers on my 64 today and they won't fit angle plug heads. Do headers really improve performance of a street engine? I expect lots of opinions here so does anyone have any real factual data?

Thanks,
Rex

bcwaller

Angle plugs! I went through that as well. I swear I bought and returned five sets of headers that either worked with the plugs but mot the car, or the car and not the plugs. The headers I ended up with were put on with the plugs installed, because I'm not sure if I can remove one plug unless I break it off!

I would say that headers do make a difference, but it also depends on if you will use that difference.

Good luck!

Dr L-88

Anybody here have any experience with this company?

https://www.castheads.com/manifolds-...ust-manifolds/

Bluestripe67

An engine is an air pump! My thinking is, if everything is flowing smoothly from intake to exhaust, I believe headers will be a functional part of the process and extra power can be gained from them. How much, I have no idea. I just love the changed exhaust note/tune with my side exhaust. And the constant 20mpg must be a partial byproduct of all this. Dennis

Kerrmudgeon

I just forget the make of header I bought way back when on my 66, but I loved the fact that my angle plugs heads gave me extra clearance for wires and installation because of the angle. I thought they were Hedman? Straight plug heads plugs were always really close to the primary tubes....

Those were GM angle heads btw.

wmf62

https://www.sandersonheaders.com/san...ategory_id=648

and a google search

https://www.google.com/webhp#q=block...gle+plug+heads

Bill

tuxnharley

Long tube or shorty headers?

Long tubes are more effective over a wider rpm range, but in either case the dyno tests I remember seeing is that there isn't really much significant improvement under about 4500/5000 rpm.

How do you intend to drive the car...............?

63 340HP

My solution with my 350's angle plug phase VI Bowtie heads was Brzezinski Racing Products ported 2.5 inch exhaust manifolds:

https://www.castheads.com/manifolds-...ust-manifolds/

They are fairly well finished as delivered (ported better on the inside, than reflected in the quality of the outside texture). I spent some time doing what was probably unnecessary additional inside and outside grinding and polishing of casting flash.

I also had them Jet-Hot coated by a somewhat local shop and they are aging nicely.

http://www.jet-hot.com/automotive

Computer models and engine dyno tests showed the manifold's short runners (head pipe length) cost about 10% torque up to about 4500 rpm, and less in the upper rpm range (compared to 1 3/4 by 40 inch headers). The dyno run comparison reflected less torque loss than the computer model, and opposite of old school wisdom regarding where the momentum tuning of long tubes work).

3JsVette

You can always build a "custom" set of headers. You do have experience in that endeavor.
Something to consider that would not be a lot less intense is "header modeling kits" where you build your set of headers from plastic pieces and then your model is copied and your have your set of headers that fit correctly.

Dr L-88

Good idea.....................but very expensive to build only one set. My other venture that you speak of required a dozen sets to break even, and I still have 3 sets. I actually had plans to build that style for small blocks, but didn't think the demand would be there. I'm trying to stay somewhat period correct since this car was raced in California in the 60s.

Dr L-88

Were they original GM castings or the imported castings?

I kinda like this idea...........................bolt on just like factory stuff, no modifying or fabricating to get it to work. I'm just looking for a good flowing system. I have two sets of Stahl headers so I may try them, but they're the road racing style with side pipes. Right now I'm leaning toward the Brezezinski manifolds.

Thanks,
Rex

PAmotorman

dorman sells a 2-1/2 rams horn exhaust manifold at your local auto parts like these. http://www.speedwaymotors.com/Corvet...air,58966.html with a closed exhaust system I don't think you will see much HP pick up with headers over rams horns

63 340HP

The castings begin the same Chinese manifolds as the Dorman Products (same foundry). I looked at porting the Dorman manifolda myself, but the cnc porting is much cleaner and easier.







It is hard to get a photo of the result but they work well with the angle plug heads, the factory ignition tin, and raised valve covers that clear stud girdles. As you can see they also clear the Borgenson power steering box with ample room.

Few non-NCRS people notice any difference from stock components.

buns

Picture below is of my Trik Flow heads with angled plugs, and unknown make of headers. As you can see, the plugs are angled away from the headers, giving mucho clearance.

So, I'm wondering, do some heads actually angle the plug toward the headers, thus reducing clearance?





.

ptjsk

Hey Rex,

I've had good luck with "Doug's" headers.

Of course I have a C1, but I have aluminum heads with angle plugs and Doug's stated they would work, and they do!

Additionally, I purchased a set for my '55 Nomad and they fit as well. Again angle plugs, and they fit just as how Doug's said they would.

Of course I ended up going a different direction on the Nomad, but the point remains that I had good luck on both applications.

Pat

wmf62

https://www.sandersonheaders.com/san...eader-set.html

https://www.sandersonheaders.com/san...eader-set.html

http://www.hotrod.com/articles/0601sr-exhaust-headers/

Bill

DAN70

I use Accel Shorty Plugs with my Chevy angle plug heads for additional clearance.

rfn026

I have headers on my '85 track car. I have no reason to put them on my '58. These are two different cars with very different purposes.

I really don't see much use for headers on a street car. Maybe that's just me. Will you actually feel the difference on the street? How often do you go to the redline?


Now these I like.

Richard Newton
Headers 101

jerrybramlett

Probably not, unless your engine is already running too rich or you alter your fuel delivery system to provide a richer mixture. In theory, reducing exhaust back-pressure leans the combustion mixture. The only way to get more power with headers is to compensate for this.

I've done chassis dyno testing to compare a stock 327/360hp FI engine with and without tubing headers. The peak power didn't change significantly when the headers were routed through the stock mufflers.

stratplus

I have a 64 engine and Hedmans's.

By removing the original ramhorns and adding Hedman headers and removing the stock sized pipe and changing to 2 and 1/2 inch pipe (except for the last foot to go through the bumpers) and removing whatever mufflers I had and changed to FlowMaster 44's I gained:

70.57 increased horsepower.
63.64 increased torque.

Your gain should be better because you wont have to go through the bumper.