59AB - Headers vs stock exhaust manifolds?

[PGBuick]

I have a pretty stock '48 flathead and not looking to maximize HP or performance. It's sitting in my '36 chassis with a vega steering box and cross steer setup with stock wishbones. I found a set of cast iron exhaust manifolds that I can make work for a true dual exhaust. I also found a set of headers from Flowtech (12701-7FLT) that will fit around the steering box and dipstick with slight massaging.
The headers have 1.5" diameter tubes, which are much bigger than the 1 3/8" exhaust ports in the block. What is the consensus from the flathead wisdom chiefs on exhaust flow, issues, problems, prior experience, etc, in choosing what to go with?
Thanks in advance for your shared knowledge.

[oldford2]

The original exhaust system can easily handle the outflow but there has been a consensus that a dual system had advantages like a better sound with your choice of mufflers and possibility of a little improved air flow. Don't expect to feel a performance change but the new sound may make you imagine it
When fitting your drivers side pipe be sure you check it with the clutch depressed.
John

[Seth Swoboda]

I have Fenton headers on an engine and Red's Headers on another. Personally, I will never put headers and dual exhaust on another flathead. I'm over it.

[Admiral]

I like headers on a flathead, but not for performance. With this engine's torturous exhaust routing through the block, I doubt headers increase power at all, but I like them because they can clean up the exhaust routing and I imagine they also help get heat out of the engine/engine compartment. Headers can also save a good bit of weight compared to cast-iron manifolds.

[flat-v8]

I love the sound of these Fenton cast iron headers and no mufflers, but OMG very hard to get them to fit around steering box. When they get hot they warm up the gear oil!

[cas3]

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I run Fentons on a 59a motor in a 34, dual straight 1 3/4" pipes...love the sound. I had to modify the dipstick tube to clear the header. not a big deal. Used an inverted flare fitting on the pan, then IIRC 3/8 tube up to the same height as the original tube, bent to fit. Then a modern skinny dipstick that will flex around the curves with a flathead handle brazed on top to fool you guys !

[Ol' Ron]

John Lawsons Book has a series of tests that shown tha duals ans headers offers nothing than aesthetics to the car. They look good and sound good. Nothing wrong with that.
Gramps

[blucar]

Headers are a waste of money when compared to stock cast iron manifolds on a flat head V8. I have a well built 59AB engine in my '36, it has all of the common performance features of the early '50's except for headers.
I bought a set of Douglas headers for my engine when it was built in the spring of '54, could not get the left header to clear the '40 steering gears. Did some extensive hammer work to the center pipe of the headers to no avail, ended up using the stock 36 log style cast iron manifolds. The headers have hung on the wall in my garage every since, they make nice conversation pieces.
I street raced my car on regular basis, and on several occasions took it out to the local drag strip where it always performed very well.

[Bill OH]

The stock manifolds are sufficient - headers are not necessary. What does help is a straight thru muffler and a tail pipe the same size as the exhaust pipe. Back off the vacuum brake to full off, install Stromberg Model 48 carb, and you will notice the difference in performance.

[blucar]

I have responded to the header vs stock manifold question many times throughout the years. I like many other people thought that exhaust noise equated to more power, hay look at me, I go fast!
In 1955 I got tired of being pulled over by the police due to the excessive noise my steel pack mufflers made. Of course one I was stopped for excessive noise the officer would find other issues to cite me for.
In 1955 I took the Douglas steel packs off of the car, replacing them with stock chambered mufflers on both sides with custom made 2" tail pipes.
The silence was golden, never received another excessive noise ticket, and the engine ran very well, I could actually hear the purr of a well built engine and the radio.
About twenty years ago I had a new exhaust system custom built for the '36, 2" pipes from the engine to the rear bumper with stock chambered mufflers.
On the idle you can hear the cam overlap in the pipes, which goes away once the RPM's are brought up.
I guess I should mention that during the early '50's I managed a performance exhaust shop in Eastern Idaho. Our bread and butter business was stock exhaust systems, mufflers and tail pipes. During the time I was involved with the business I/we installed custom exhaust systems, headers, split manifolds, etc., on just about every vehicle on the road, Buick/Packard, Chrysler Hemi's and in-lines, Chevy's even a Crosley 4 cylinder OHV engine.

[tubman]

I think one of the benefits of A/C in cars is that now the cops now cruise around with the windows up and A/C on. That way, they can't hear the loud pipes and go blithely on their way. Think about it; when is the last time that you (or anyone you know) got a ticket for a loud exhaust?

[flatford8]

I think you’re on to something with the “windows up” idea. I hear vehicles, especially diesel pickups, that are way louder than they need to be. If I was a cop, and heard it, I’d pull them over for being an a$$hole for making so much noise ……….Mark

[47topless]

Originally Posted by Bill OH

The stock manifolds are sufficient - headers are not necessary. What does help is a straight thru muffler and a tail pipe the same size as the exhaust pipe. Back off the vacuum brake to full off, install Stromberg Model 48 carb, and you will notice the difference in performance.

Bill,
Would you please explain your recommendation for a 48 carb, rather than a 94, on this engine?
Thank you,
Phil

[38 coupe]

Bill is probably recommending a 48 since Stromberg 48 carburetors have a larger diameter venturi than Stromberg 97 units. The 48 flows a bit more than the 97 at wide open throttle.

[47topless]

Originally Posted by 38 coupe

Bill is probably recommending a 48 since Stromberg 48 carburetors have a larger diameter venturi than Stromberg 97 units. The 48 flows a bit more than the 97 at wide open throttle.

Sure, thank you. But how about the Stromberg 48 compared with the Holley 94? It is my understanding that the 59AB's came with the Holley 94s. I ask, because, I have a 1947 59AB and it uses a Stromberg 94. Maybe I should be looking for a 48?

[Bill OH]

The big objection I have with the 94 is the power valve - diaphram ruptures and gasoline into the crankcase. The Stromberg 97 and the 48 have mechanical power valves - no problem. The Stromberg 48 has a larger venturi than either the 94 or 97 and thus flows more air and the more air you can get thru the engine, the greater the power.

[junkbrick]

We had a customer with a .060 over Merc come to our shop for some dyno tuning, the car had stock manifolds and exhaust. Cannot recall the entire build of the engine other than a dual manifold. What I do remember is it made right at 83 whp. A few months later he called us up and wanted us to re-tune it for his dual exhaust system. It had a set of tubular headers and some glass packs. We strapped it down and made a few pulls...timing was good and air/fuel was spot on. It made 82 whp that day...the reason? The weather. Our first dyno session was early in the year, the second was right in the middle of summer. I always wanted to get that car back on the dyno on a cool day for an apples to apples comparison. I have stock manifolds on my 36 with duals and some no-name glass packs. Its all about the sound.

[Bill OH]

I had a 61 Ford with a 352ci, stick shift w over drive, 2 bl card and single exhaust - top speed 104. Added dual exhaust - top speed 113. Added 4 bl and top speed 120.

[Ol' Ron]

Afew years ago I was parked at the local Grocery store. When I started the engine an old fellow walked up to me and said. That the best sounding engine I've heard in years. Sounds like an old flathead Ford. I pu;lled the 47 Int over and opened the hood for him 51 Merc engine duals with smities.

[junkbrick]

Originally Posted by Ol' Ron

Afew years ago I was parked at the local Grocery store. When I started the engine an old fellow walked up to me and said. That the best sounding engine I've heard in years. Sounds like an old flathead Ford. I pu;lled the 47 Int over and opened the hood for him 51 Merc engine duals with smities.

You were the highlight of his day...he probably told the story of your car to everybody he could



My 36 has a .120" over Merc with a 400jr...duals with smithy's. Overkill on the cam, but it sounds great (to me at least!)