How do you "split" a 6-cyl exhaust manifold?

Are they being reproduced by anyone? Making a fifties hot rod '56 chevy & want to do it like they did "back in the day". Never seen (or heard) a car with a split manifold...but I hear they sound *****in"! Would a pair of Smithy's mufflers sound right? Would the mufflers be mounted close to the engine or close to the bumper? Should the exhaust go all the way to the rear bumper, or exit in front of the rear wheels? What are "dump tubes" and where are they located? I've heard about "echo cans" being used for tail pipes and believe old drive shafts with the ends cut off were used. About how long were they, and were they used in cinjunction with mufflers or straight thru?
Thanx, and remember...If you fight one bean, you have to fight the whole burrittio!

 

my formula on a 235 is i find a donnor manifold for the second pipe and cut off the flange drill out a hole in my 235 manifold and weld it on in a location that works, i also cut a slot in the 235 manifold and slide in a block off plate to divide up the ports, this plate wil increase the rap. i use cherry bomb mufflers also for the rap. look inside the muffler for drilled holes in the inner tube not stamped louvers as they kill some of the rap.also mount the mufflers up front for more rap. i dont know about cans on the end but i would venture this would give some echo effect.

 

i saw the manifold off behind the box under the carb, then again just ahead of the front port on the rear piece. Weld in a sharp bent pipe and a plate on the front half, and you're away. More tailpipe length makes a better sound, less roar, more rap. And yes, they sound nasty!

 

There is a guy on the shoeboxford.com web site that does it.

 

These were modified,not by me,with the cut offs from chevy exhaust headers.You could put the flanges wherever the application called for.I'm using a similiar pair on my build. Bungs and tubes can be added for intake manifold heat.

 

Which engine are you using, the 235 still? If so there are repops of the Fenton and the Nicson cast headers (if they fit Chevy, I'm gathering pieces for a Jimmy).

FWIW I have heard of people welding on an extra outlet and putting a plate with a hole in it between them inside the manifold (adjusting the tone of the exhaust by changing the size of the hole).

If you need more info check out Inliners.org

 

The most popular method in So Ca was to weld a plate into the manifold and weld on another flange. I don't remember ever seeing a manifold cut in 2 pieces at that time. There is usually a hole in the plate, most muffler shops recommended a hole the size of a dime. You get the most "Rap" with out a hole. The larger the hole meant less "Rap". We used to call a Chevy 6 with dual pipes a "Mexican Jaguar"
Later on , in the "60"'s I bought a rear section that resembled a half header from Spiegle's ( not sure of spelling ) Mail order catalog. To use this you did cut the manifold and replace rear section with new part.
Echo cans were just large diameter tips as they were called. The drive shafts were used mostly on race cars. the drive shaft are out of early Ford V8's I have one cut in 2 on my Lakes Modified. When I was in high school in the early "60"'s a guy had a 36 chevy coupe with a split manifold and his tail pipes were made from 6" light weight irrigation pipe. Now that was loud!

 

No need to cut manifold apart....put a plate inside the heat box to block off rear half..put a hole in plate.add extra outlet on blocked off half...no hole in plate has same effect as blocking off heat riser in a flathead..more noise.rap.what ever you want to call it..If you can find any old steelpac Mufflers.they sound the best..Much deeper rumble....

 

Anyone currently splitting a manifold want to do a tech post?

 

FWIW for mufflers I have had recommended to me the Brockman Mellowtones (steelpacks) or the Flowmaster Huspower II's. They both supposedly give the sound the Smittys used to (going on heresay here, I haven't heard the old vs new Smittys so I don't know, but supposedly the new ones are gl*** packs and don't sound the same, or so I'm told).

Or real small pipes, with no mufflers (1.25" or smaller).

 

Spend a little, get the Fenton cast iron split manifolds from Patrick's in Arizona.

These are 3 & 3, the Southern Calif guys used to split them 4 & 2, (even saw a 5 &1!)
made 'em rap loud enough when straight (no mufflers) to break large store windows!
Toody LaHerran backed his black '50 Chevy up on the sidewalk in front of Hart's Dep't store and rapped it a coupla times, that big gl***window shattered! His were split 4 & 2.

 

I am fixing to split one for a 216 in the next couple of weeks and will consider doing a tech post if anyone is interested.

 

Please do. I'm interested.

 

Moocho Gracias fellow HAMB'rs. I learned more in 5 minutes, reading your replys than I have in the last 40 years just poking around. My little 235 chevy will be rappin her heart out thanks to you guys!

 

As I requested a few posts up, please do. Thanks in advance.

 

How do you split an exhaust manifold 4x2? I've heard of it but cant seem to grasp it.

 

I had the maifold split on my '56 Chev pickup. 25 years ago. The old er gentleman cut a hole just behind the stock flange and welded a pipe there to attach the exhaust pipe. He then welded a washer inside that somewhat seperate the two halves. He used a washer so that there was some exhaust pressue between the two halves of the manifold. I then used gl*** paks. The exhaust exits just in front of the rear tire, one on each side. I love the way it sounds! It will rattle windows and has quite a bark at about 3,000 rpm.

 

This is the split I did on my modified, when I cut the hole for the new flange we welded a block off plate inside to split the manifold.Flange added from donor 235 manifold to the front half for more room around the clutch and throttle linkage.Be aware of the generator position also

 

E-bay has someone selling a book, $6.50, and promises tech support. Search Fenton, or split exhaust manifold.

 

Here's a couple of pics of one I did.

 

I like what my buddy BJ did

 

The split of the cylinders front vs. rear is not accident or convenience, it's based on the firing order.
For maximum performance, it's important that the front vs. rear cylinder groups be completely separated.
If not, once the cam timing reaches a critical point there is shared exhaust re-breathing between the 2 groups unless the manifolds are separate.
To increase efficiency without $$$ or changing the appearance, use the thickest exhaust header flange you can find between the manifolds and the head (extra gasket and longer studs). Extending the manifold out improves flow a bit without penalty - even 1/2" is helpful.
The best place for the outlet for flow is also the most annoying to make: in between the ports (rather than at one end).

 

Not to hijack but do you have more pics and details on this car?

 

I don't have any more right now but it is being built by BJ Burkdoll who owns and operates Autobody Express with his dad Jim Burkdoll.

 

Here is a tech on splitting one.
http://www.chevytalk.org/fusionbb/s...st/1293298/hl/splitting/fromsearch/1/#1293298

 

I had the same question when i wanted a new exhaust system on my 54 chevy with a 235. i bought some headers for it, n i ran 1.75 pipes all the way back. that sumamabich rapped!!! then i went and added a steel pack muffler 12" to one pipe, then i didnt like it... not that much rapp. but straight pipes with headerts sounds bad***,thts the only way 2 do it!!