brotherGood

I'm thinking about going with headers on my '69 442. Not for sure as I'm trying to keep it as close to stock appearing (although the wheels blow that out of the water) but being that I'm now .040" over and will most likely have a bigger cam, I'm wondering if headers would be more necessary. My concern is, when I spoke to the rep at Inline Tube over the summer in regards to brake parts (Disc/Drum), the first question he asked was whether I'd have headers on the car or not-as if that made a difference. At the time, I told him no as I was (and still am) quite naïve at what it'd take to save the original engine. I'm not looking for a race car, just a cruiser/show car but at the same time I don't want to choke out what the engine will be capable of if it'd be that much of a difference.

I guess the first question would be can I run them? Second, is it worth the hassle?

Thanks

oldcutlass

You'll get many different answers, the ones who hate headers and the ones who love them. I personally like long tube headers, it's the least expensive power adder you can get. To the inexperienced they are a pain in the butt sometimes to install due to minor interference issues that may arise in the installation that need to be overcome. Once properly installed they will outlast your car and be leak free. If you're planning on shorties, they don't bring much to the table for performance over manifolds, but look nice.

acavagnaro

I think your breathing limitation on the 400G will likely be on the intake side. They can't hurt but, honestly, I'm not sure they're worth it for the way you describe your usage with the car. The original W/Z manifolds flow well and would probably make your car more interesting to the knowledgeable Olds observer than aftermarket headers but, your call. The headers will bump output but whether or not it's worth it is up to you.

brotherGood

I put a set of long tubes on my SBM and wasn't prepared for the massive change in the tuning after install. If I go ahead and get them, it'll be decided on prior to the engine hitting a dyno (i.e. tuned with the headers) it's just a matter of..why did they ask as if it would create a problem?

brotherGood

Is the limitation via intake or heads?

Oldsmaniac

My opinion is to forget the headers, more hassle than they are worth for a street car, the rebuild if stock will hardly benefit from headers at all. Things that MAY happen with headers... low hanging, gasket failure at head and collector, bolts coming loose, interference with bracketry and brake lines and battery cables, exhaust pipe connection from header to pipe troubles, starter fit issues, and probably a few more.

joe_padavano

The engine needs to function as a system. Anything that improves the movement of air in and out of the cylinders will increase HP. Properly designed full length headers have been shown repeatedly to free up 20-30 HP lost in the stock exhaust. Yes, W/Z manifolds are better than others, but still not as good as real headers. Yes, there will be fitment and ground clearance and gasket problems. That's life. If you can't live with that, keep the manifolds. If the extra HP is worth the hassle, get real headers.

BangScreech4-4-2

Much depends on your cam choice. Don't know how "big" you're planning on going, but I have a CC XE262H (218/224 @ 0.050, .462/.469 @ 1.5 RR, 110 LSA) in my 400, which is about as crazy as I wanted to get given the G-block's inherent limitations. Works fine with the factory W/Zs and I've never seriously thought about getting headers.

If @cutlassefi chimes in, he will likely recommend a single pattern grind and I don't know how this might affect the desirability of headers.

Rallye469

I've never had a set of headers that didn't help a car out.
I've also rarely experienced a header gasket blow out.

So why did they want to know about headers?
Were they worried that the header could hit the A-arm?
Or that the brake junction block would get in the way or overheat the brake fluid?

-peter

brotherGood

that's what I'm wondering as well...maybe the junction block/boiling fluid?

If the factory manifolds had reasonably well flow, I'll probably just stick with them. I'm coming from smog-era v8s making 145hp from the factory..so my nature is to assume everything is choked out. If that's not the case with these, then it should be just fine for what I'm doing with the car.

BackInTheGame

They asked whether you will be running headers because it will dictate routing of the brake lines from the MC to the distribution block, and from the block to the wheels. If you run headers, you will need to move the distribution block. Some folks just gently bend the lines and put the block on the top of the frame rail. It matters because the headers radiate heat, and if you don't move the distribution block, you run the chance of boiling your brake fluid. I replumbed from the MC to the distribution block and moved the block down onto the inner frame rail. It is hard to tell from the angle of the photo below, but there is about 5 inches between the DB and the header. As stated above headers are good for a bolt on 15-20, or so, HP. Yes you've got to tweak your carb to make the most of it. But you will be doing that anyway if you are boring the block and adding a cam. Have at it! You'll be glad you did. Not sure why some have problems with headers and their installation. I've put them on two '68s and one '69. The '69 and one of the '68s are 4-4-2s and 4-speeds. It can be fun lining up the bell crank, you might need an extra hand... No issues whatsoever, in the end. Never had them leak, either.

Here is where I mounted my distribution block.

cutlassefi

^^^^^^
The only two things that help HP AND efficiency are increasing compression and installing headers. The flow of any manifold doesn’t mean squat. It’s the tuning pulses of the exhaust that are enhanced by installing even just a decent set of headers.
Hope this helps.