https://www.ebay.com/itm/383411379675?ul_noapp=true

I know some of their headers have been discussed but does anybody have experience with these replacement for W/Z? They look pretty slick and Im curious about fit and performance.

 

I'll find out. I'm going to buy a set today. Thanks for posting it.

 

Cool, keep us posted.

 

I purchased a set of these last summer for my '69 442 (400G). The engine is fairly modified; aluminum heads, performer intake, Mondello cam but I was still running the original W/Z manifolds only because I really didn't want to put long tube headers on it. I went back and forth on that decision for a long time so when I saw these, they looked like a good compromise. I have a 2.5" Flowmaster 409 stainless exhaust on it with Pypes 2.5" stainless downpipes off the factory manifolds so everything was clean and routed as original.
These short tube headers did exactly what is advertised. I was able to swap them in place of the original manifolds and the downpipes bolted up exactly as before. Quality is excellent (I went with the natural finish - not polished) and fit/finish really couldn't be better. They come with a quality gasket and I went with Stage8 fasteners to (hopefully) avoid loose bolts and leaks at the flange. They've been on since last July and I haven't had a single problem.
OK - now for the obvious - was there any noticeable performance difference? Honestly, no. Maybe a little on the butt dyno but I can't really say I noticed any real difference. Possibly a little more mid-range punch. I'm a turbo engineer so I know more than a little about exhaust flow vs. engine performance. I wasn't really expecting a big improvement over the factory manifolds given the necessary restrictive nature of the design and outlet flanges. My motivation was more to see if a change in exhaust flow made any difference for the aluminum heads. I'm still curious what long tubes would do but I'll never go that far on this car.
One last comment - if your car has AC be prepared for a battle with the rear most passenger side flange bolt. It's pretty much impossible to start after the header is in place. You'll notice some of the holes on the flanges are slotted. This was smart as you really need to partially thread the bolt first and then fit the header flange over the bolt head and slide it forward into place. Even then just getting enough torque on that one bolt was a challenge. Another reason I was glad I went with the Stage 8 fasteners. If I had to crawl under the car and contort myself to retighten this one bolt every few months I'd give up! Of course this challenge is due to the AC location and not the headers. Over-all I would highly recommend these.
Hope this helps.

 

I have these on my 80 cutlass 455 and am very happy with them .No fitment issues.x2 on the rear most bolt under the ac box ,its tricky for sure.I cant speak for performance differences but they sound great and downpipes bolted right up.

 

There has been much argument over gains over cast iron manifolds. Over the W/Z manifolds, maybe 10-15 HP and torque, will you feel it, especially on a 400+ HP engine, probably not. You probably won't feel the 30 HP gained with long tubes. What you will feel and hear is your long tubes scraping on the ground. These with stock pipes and anywhere near stock height, never on an A body. My G body is a different story, exhaust has to be tucked up high for 0 road rash.

 

Good to know about fit which doesn't seem to be an issue.I guess the only real way is to dyno test these vs cast to see exactly what the difference is? After all, the horse power gain is the whole point of these.

 

I like these,I bought a set to use on my upcoming engine build.
For curiosity I would like to see a dyno test comparing these shorties to stock manifolds.
With me horse power is not the whole point of these,if I was after every last HP,I would use long tube headers.
I wanted something that looked different then stock but not full length headers.
A bonus for me,I picked up the polished version to go along with the bling on my engine.

 

Thornton brought these to market to give us Olds people options,not compete with other headers or manifolds,and I'm thankful they did.

 

I have a set of the small block version I’m currently in the process of installing on my g body. I will attest to the comments on construction quality. They’ll be easier to install than it was to remove the old manifolds, but I may have to remove the steering shaft, not sure yet. I’ll have to relocate my O2 sensor to the start of the downpipe on the starboard side, no biggie. Brand new exhaust from the manifolds back. That rear bolt on the starboard side does seem to be a pain because of the tight curve of the tube; bolt must be inserted with the header off the car and then installed.

With them side by side, there’s no way they can’t pick up a little power over the stock manifolds. How much though is anyone’s guess.

 

Without a doubt, they are cool looking. First, they are not equal length tubes. Second, they are to short for any ram tuning or scavenge waves in normal RPM ranges. They could streamline the exhaust flow and reduce turbulence. Horsepower gains would be minimal if any.

 

Yes,..But they look COOL!!!!!😁. If we wanted to go faster, we’d buy something newer, faster and handled way better! I’d say at this stage in the game we drive these cars because they exude personality and style. They do that very well!

 

Are you going with A body down pipes or custom exhaust? Did you have stock 442 exhaust before this?