Inliners International Forums General Discussion Engines langdons headers

I recently got a set of langdons cast iron headers for a 67 chevy truck with a 292 engine.What manifold gasket is used? A stock gasket or something else? Mr.Langdon advised against using Smithys mufflers.Ive got a pair of 30" Smithys new.Ive heard these mufflers on a 50 plymouth flathead,thats why I got them.
I know they wont sound the same on my truck but if its close Ill be happy. Muley

Stock gasket is fine.
Post a link for the Smithys
http://pertronix.com/prod/ex/smithy/default.aspx?

Not sure why you should not use those? Bad design,back pressure?

MBHD

No personal experience, but judging by the OD vs. inlet diameter the internal volume is pretty small. It's a straight-through design (?) so it won't affect power much (if at all) but it would be quieter with more volume.

BTW: the usual "tell" visual for straight-through is that the inlet and outlet are on the same centerline (if not, almost always reverse-flow where both pipes are parallel inside an open box with their openings on opposite ends).
However: some apparently straight mufflers have a completely closed inlet tube at the far end, holes drilled or punched emptying into the shell, and the outlet only connected to the shell interior - not the inlet. Backpressure may be very high, depending on what the perforations look like.

So what the General consensus about Langston manifolds I am considering getting a set sometime soon. I am a bit put off by tubular style leaky headers. But are there any noticeable gains from the slip manifold? I like the sound of a good old fashioned glass pack on my single pipe would a "Y" pipe get the same results If I had bigger piping after the "Y"?

Well,,the only dyno testing I know of w/Langdons exhaust manifolds were when Tlowe dynoed a 250 L6.

He was saying the manifolds held there own as compared to the tubular headers & lost power up top compared to the headers.

But,,,,,,,,,,this was the run/testing when the 250's damper destroyed the crankshaft & took out the fluid damper also.

When this happened several times on my 250(stock damper),the engine had lost a lot of power due to the damper not actually working to dampen out the vibrations.

I asked Tlowe if he could perform the 250 dyno test again after he installed another crankshaft & HP SBC stock damper w/Langdons manifolds,but he did not want to do so,,,,so as I see it,that dyno test with the tubular headers VS Langdons manifolds was not a good comparison & inconclusive.
Really needs another go @ it for a better comparision IMO.

I think Langdons manifolds look good & should not be that far off as far as HP & torque as compared to tubular headers for a typicle street application,,plus, I am sure less leaks.
No first hand experience w/them ,but I considered using his manifolds & feed a turbochager until I found out SPA makes the turbo manifold,but still yet,I would use those manifolds to feed a turbo over a stock manifold.

MBHD

according to all the turbo muffler folks, their products outflow all the "straight-thru stuff" (THEY WOULDN'T LIE WOULD THEY?), and almost all the turbo styles are reverse-flow but with much larger internal capacities. Trucks made after the turn of the century (some even before) have reverse flows, some big as trash cans. But nothing can destroy plate glass like a Smitthy's (be it glass or steel pack) RRRAAAAP! Sic "em!!!

last year i put in a 250 in my 52 chevy deluxe and had a hard time finding a new exhaust manifold as all the old ones i found were bad.then i found a place that has new manifolds that have larger flow no heat riser and 2.5 outlet.
these manifolds are used on industrial 292 engines.
works great and looks great....... http://www.the-co.com ....is the web site when you get to this page Click on Oline parts store..then...go to engines....then to manifold and you will see 292 listed

Love to see photo of that manifold on your 52.. Could not clear the emergency brake linkage when I enstalled one on my 50 Chevy.

i did run into clearance problems with the e brake also ,so i moved the e brake assembly over to the left by one inch clears the manifold and you donn`t notice it in the car and no problems with it getting in the way while driving when moved
not sure how to post a picture on this site,i will soon as i can figure this out

"Straight through" only means there's no change in the diameter, but there's always restriction from the wall contact (even a plain tube has some), and especially those with the punched louvers facing into the flow stream. A reverse flow can be lower restriction, if it's big enough.
To give some idea of how big a muffler has to be before it can rely on size alone for silencing: 15 × cylinder volume, or (for a 235) 589 in.3. That's a cylinder 5" diameter and 30" long.

IMHO a Y pipe is a bad idea for any performance on an L6. The overlapping firing order of the 1-2-3 front and 4-5-6 rear cylinder groups only works if they're separated as long as possible (and don't get any interference from the other group). it's not an accident that an XK-E has twin pipes all the way back.

I think straight through means,there are no changes in direction
of air/exhaust flow w/in the muffler?

You can have a straight through muffler that has a 2,5" inlet & a 3" exit.


MBHD

I used to run 2" dual exhaust.Clifford headers 3 & 3.

I ran the same Clifford headers & switched over to running a "Y" pipe into a single 3" pipe all the way to the rear bumper,it actually ran better IMO.

I did however like the dual exaust sound better than a single made it sounded like a Datsun 240-280 L6 Z engine.


MBHD

straight through means,there are no changes in direction
of air/exhaust flow w/in the muffler

True, doesn't have to be constant size.

There's a critical cam duration (especially overlap) window below which joining the pipes has little effect, but as the duration goes above (roughly) 280°, separate pipes pull ahead.