Twin exhaust manifold for '52 308

[Deleted User]
edited November -1 in HUDSON
I am hoping the tax man will be good to me in a couple of months and one of the things I would love to do is put dual exhaust on my 308 with Twin-H. I currently have an exhaust manifold with a single out and it is my understanding that a dual exhaust manifold was a 7X option. I would like to keep my car as period as possible and am actually interested in any and all bolt-on 7X mods, but I believe most require actual permanent changes to the engine.



Is my information right?

Does anyone sell the dual exhaust manifolds? I have been looking at eBay, but have not turned up anything.

Headers are not period, right?
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Comments

  • 53jetman
    53jetman Senior Contributor
    Micheal - Here is a picture of a reproduction dual exhaust manifold outlet (7X) that was made available a couple of years ago. I don't believe they are still being reproduced at this time. However, I thought you'd like to see a picture of what you are looking for.



    Jerry

    53jetmanAttachment not found.
  • Thanks for the picture Jerry. Am I to understand that the exhaust manifold is the same but it is an adapter I bolt on to make it dual exhaust? :confused: I thought it was a completely different manifold that actually increased Horsepower and outputted dual exhaust.
  • mjsandbe wrote:
    Thanks for the picture Jerry. Am I to understand that the exhaust manifold is the same but it is an adapter I bolt on to make it dual exhaust? :confused: I thought it was a completely different manifold that actually increased Horsepower and outputted dual exhaust.
    Hudson made no dual exhaust manifold that had 2 outlets. It was just an adapter that bolted to the manifold. You could grind away material inside the manifold, elimInate the heat riser and you then had the manifold the racers used. Walt.
  • nick s
    nick s Senior Contributor
    mjsandbe wrote:
    Thanks for the picture Jerry. Am I to understand that the exhaust manifold is the same but it is an adapter I bolt on to make it dual exhaust? :confused: I thought it was a completely different manifold that actually increased Horsepower and outputted dual exhaust.
    The picture is of a part that was built in the spirit of the origonal. The origonal was a split manifold with no damper and an outlet elbow similar to the one pictured. these repro's are made to bolt in place of the outlet on the stock manifold which is different than the split.
  • I am am confused. The way I am reading it Walt & Nick seem to be saying different things about he 308 7X exhaust manifold. Can anyone clear up my confusion?
  • dougson
    dougson Senior Contributor
    mjsandbe wrote:
    I am am confused. The way I am reading it Walt & Nick seem to be saying different things about he 308 7X exhaust manifold. Can anyone clear up my confusion?



    They're both right, but expressing it differently. The exhaust manifold itself was never modified by the factory. Instead the factory offered an adapter that bolted to the manifold outlet and had two outlets. In effect, exhaust flow was not changed until it reached the adapter, then flowed through one of two pipes. Really was not a performance enhancer, but probably helped a little.
  • OK, I think I am starting to get it. A single bolt on part split the exhaust off of the manifold. That leaves one question on this; Were the exhaust manifold internal modifications were part of "7X" or something additional that racers did?



    Anyone sell the reproduction part for splitting the exhaust?



    Am I correct that headers such as the Clifford Dual Outlet Headers HUDSON 262-308 are a more recent option and would not be period? I am really not sure, I see Clifford referred to in some Fabulous Hudson Hornet racing information.
  • dougson
    dougson Senior Contributor
    Cliiford headers were not part of the 7X package, they were built later. Other types of true headers have been built (one on Ebay recently). A lot of folks who have built 7X engines use the header because it is a vast improvement over the original splitter. Original 7X exhaust splitters are rarer than bird teeth. The reproduction is probably no longer available. As far as the internals in the exhaust, my guess is that the racers stripped them out.
  • nick s
    nick s Senior Contributor
    dougson wrote:
    They're both right, but expressing it differently. The exhaust manifold itself was never modified by the factory. Instead the factory offered an adapter that bolted to the manifold outlet and had two outlets. In effect, exhaust flow was not changed until it reached the adapter, then flowed through one of two pipes. Really was not a performance enhancer, but probably helped a little.
    No, Nick is disputing Walt's claim. The factory 7x manifold was completely split. there is no provision for the butterfly in the casting and the outlet elbow is similar to the repro, actually if i recall the repro was patterened using an orig and still has the hudson part number but the two are not interchangeable because the manifolds are different.
  • dougson
    dougson Senior Contributor
    I've attached photos of what is supposed to represent the actual exhaust setup on a 7X. There is a single outlet but the outlet itself is split internally, apparently separating the exhaust from the rear cylinders from the front. The split outlet is different from the dual exhaust "adapter" although they look similar. According the site these photos came from, the dual pipes had to rejoin to comply with NASCAR rules. Hope this helps.
  • SuperDave
    SuperDave Senior Contributor
    This is a picture of a suposedly factory 7X manifold I took at during the National this year. I don't recall if this was at Millers or the Chrysler Museum.. most likely Millers. Notice no heatriser.. Hope this helps.:)
  • Hal
    Hal Senior Contributor
    7X factory manifold part number 307606 splits the exhaust internally and the split continues into the cast iron elbow part number 307608. 307608 will not fit a standard Hudson exhaust manifold. Later reproduction elbow does appear similar to 307608 and has HUDSON on the casting (unlike 307608) and bears the number 30 608X (the "7" position is blank). It will only fit the Hudson standard exhaust manifold. The later production piece is a fabulous piece and (if you can find one) would surely be dramatically less expensive than a full 7X set up. Ask if I can be of any more assistance or describe anything better -- I'm not an expert by any means, but I have both systems right here.



    Hudsonly,



    Hal
  • RL Chilton
    RL Chilton Administrator, Member
    All good info, here Michael. And if you are interested, I have a reproduction splitter exactly like the photo from Super Dave. I have decided not to use it for the 'vert and go with headers. If interested, I will sell it for $225, which is what I paid for it. It is unused and never been mounted to a car. Can e-mail pics, if you wish.

    Super Dave's photo is from Miller Motors, I believe.
  • As usual this group exceeds my expectations when it comes to knowledge and willingness to help. After all of the good information I believe I will just have to wait for the time my engine needs to be rebuilt before I tackle dual exhaust. I have enought on my plate with the interior at the moment, but it is damn hard not to dream. Thanks again to everyone for their responses.
  • FOR INFORMATION ONLY



    As of today, an order for 20 exhaust manifold "adapters" has been placed with a metal caster for these parts. We will have a two week wait for others ahead of this order, and the plant will be down for the holidays for one week. So, the best we can expect will be about the first of the year or soon there after. We are interested in producing these casting "adapters" for the Hudson owners, but am not able to price one yet. Will be working on the first one we get and checking shipping prices. Will let all know on this forum the price and when we expect to be able to ship. Will post new pictures if possible, otherwise will email pics to those interested. We are members of the HET club, and own one 47, one 49, and one 52. My father worked for the local Hudson dealer, and I mowed his yard.

    This "adapter" casting is using the same pattern (mold) used and sold by Danny Barrier, and later by Mark Hudson.

    If interested please email us after we post the price and we will respond. Thanks, Bob HETpbebop@gmail.com and drop the HET.
  • SuperDave wrote:
    This is a picture of a suposedly factory 7X manifold I took at during the National this year. I don't recall if this was at Millers or the Chrysler Museum.. most likely Millers. Notice no heatriser.. Hope this helps.:)
    This manifold could never be supplied by Hudson. The Hudson racers had this made, but NASCAR would never let them use it, not original. They could only use what came with the cars and this manifold would not run in cold weather. Hudson came out with the adapter, split for 2 pipes, but the heat riser had to stay in the manifold. I raced them in the 50's and I know. I ran the Daytona beach flying mile with a Hudson at 112 MPH and a MIDGET race car, V-8 60 powered and set the fastest time in 1956, 118.7 MPH. To many people talk Hudson, but how many ran them in those days. It's like I said, 7X could not be bought from Hudson, you ordered and it was put in the trunk for the dealer to install or the Hudson repair garage. Walt.
  • SuperDave
    SuperDave Senior Contributor
    The 48-54 Hudson Parts book lists several Twin exhaust pieces under "Z" which was called "Severe Usage Parts". Page 331, "Manifold-Twin exhaust" part number was 307605. There were also "kits"available listed under part number 307504. The kit supplied all the parts to convert to Twin Exhaust. These kits were listed for use on the 232,262, and 308 engines.

    These parts, very likely were not installed by the factory as Walt stated. However they were HUDSON AUTHORIZED parts or they surely would not be listed in the official issued parts book from Hudson.

    What were Nascars rules back then? I'm sure someone here has an old rule book and can chime in.. I had one and sold it many years ago. It was a very small booklet and as I recall, the book said that all parts had to be listed in the manufacturers parts book and available to the public.. or some such phrase. Im have no clue what AAA mandated, but I'm sure it was similar.

    Yep that picture I posted was from Millers and I also took a picture of the severe usage rear end! It is listed on page 329. The pic didn't come out well, so I deleted it. I can assure you it was HEAVY DUTY!
  • dougson
    dougson Senior Contributor
    The more we think we understand what was factual, the less clear it becomes. ;) Anyway, in the early days of "stock car" or circuit racing, factories were hustling to manufacture parts that would make the cars perform better. Typically it was the driver that would report to the factory any shortcomings and the engineers would design an improvement. This was especially true with Corvette when in 1956 the corporation decided it was time to prove that the car could perform. To be legal at Sebring that year, Chevrolet hastly produced a number of parts and assigned them numbers so they could be used on the four cars entered. Chevrolet eventually built about 6 production "SR" cars using these parts and a few survive today. I built a replica a few years ago and have had a lot of fun with it. The upper white car is an actual SR, my replica is below. It seems odd that Hudson never built any fully outfitted 7X cars, calling them Hornet 7Xs' or something, and offering them for sale. The cars would have then been completely legal.
  • 7XPacemaker
    7XPacemaker Senior Contributor
    walt's garage-53 wrote:
    This manifold could never be supplied by Hudson. The Hudson racers had this made, but NASCAR would never let them use it, not original. They could only use what came with the cars and this manifold would not run in cold weather. Hudson came out with the adapter, split for 2 pipes, but the heat riser had to stay in the manifold. I raced them in the 50's and I know. I ran the Daytona beach flying mile with a Hudson at 112 MPH and a MIDGET race car, V-8 60 powered and set the fastest time in 1956, 118.7 MPH. To many people talk Hudson, but how many ran them in those days. It's like I said, 7X could not be bought from Hudson, you ordered and it was put in the trunk for the dealer to install or the Hudson repair garage. Walt.



    What a WONDERFUL amateur casting job someone must have done. I never looked at my manifold that closely. I will say this- just by removing the heat riser and buying a repro adapter does NOT give you the same thing as the original thing. I know the dealer had to "install" 7X packages- but than a 7X package installed anywhere but in the trunk wouldn't be "factory" would it? It would be a dealer installed part available from the dealer. There were no original "factory" 7X cars, so were thay really legal to race?
  • Hudson308 wrote:
    So, Walt are you saying the manifold and adapter in SuperDave's picture were NOT cast by Hudson... or are you saying they were only available from Hudson "over the counter"?
    Nascar's rule book in those days stated, must be stock as delivered to the customer, with no modifications, except wheel rims could be reinforced using a center section from another wheel. Any 8 ply tire permitted. They also stated that so many cars had to be sold to qualify for a NASCAR permit. Union 76 was the only fuel you could use. Walt.
  • I have a split exhaust manifold dual-outlet setup on a Mopar slant six that uses the existing heat riser valve for good cool weather performance and proper warm-up. The following link describes it:



    http://www.dutra.org/doug/doug-sl6-exhaust/doug's-sl6-exhaust.htm



    It's a pretty nice solution, if someone was interested in designing and manufacturing a casting that could be used on the 308.



    Tom Drew
  • here is a place that splitz em! http://www.splitzmanifolds.com/
  • Hudson308 wrote:
    So, Walt are you saying the manifold and adapter in SuperDave's picture were NOT cast by Hudson... or are you saying they were only available from Hudson "over the counter"?
    No split manifold came with any Hudson from the factory. Racers built them and Hudson put a part number on them trying to help them with the cost. Very few were sold because you could not run them on a cold day, with temp under 60, car would hesitate badly. Hudson got the OK to use 7X parts for racing because it listed them as being used on export cars going to countries like Africa. The 7x items did not go to England on any cars. Walt.
  • Not the best pic of the heat riser but here are a couple shots of the complete 7X exhaust set up. Not repros. Niels
  • Nevada Hudson
    Nevada Hudson Senior Contributor
    Have one of these original split manifolds, and tried to remove it from the exhaust manifold, and one of the heads from the bolt snapped off!

    Now, any way to get the snapped bolt out?
  • nhp1127 wrote:
    Not the best pic of the heat riser but here are a couple shots of the complete 7X exhaust set up. Not repros. Niels
    It looks like your header goes into a single exhaust pipe, so where is the higher performance? You should have 2 pipes to the rear. Walt.
  • walt's garage-53 wrote:
    It looks like your header goes into a single exhaust pipe, so where is the higher performance? You should have 2 pipes to the rear. Walt.



    You are correct. If I remember, I believe it is into a 2" single exhaust with a high performance Magna flow muffler. I hadn't even thought about dual exhaust because I wanted to keep the car period correct. Were some 7X cars of the day modified to dual exhaust? If so, how is this best done with my existing set up? Note: I would only want split the exhaust after the collector.
  • RL Chilton
    RL Chilton Administrator, Member
    nhp1127 wrote:
    You are correct. If I remember, I believe it is into a 2" single exhaust with a high performance Magna flow muffler. I hadn't even thought about dual exhaust because I wanted to keep the car period correct. Were some 7X cars of the day modified to dual exhaust? If so, how is this best done with my existing set up? Note: I would only want split the exhaust after the collector.

    Niels-
    Typically a plate would be fabricated that would bolt onto your collector. Two pipes would be welded to this plate and then both of those would run to the rear. Voila'! Dual Exhaust.
  • dougson
    dougson Senior Contributor
    walt's garage-53 wrote:
    It looks like your header goes into a single exhaust pipe, so where is the higher performance? You should have 2 pipes to the rear. Walt.



    See my earlier post, supposedly the pipes had to converge for NASCAR (and AAA?) because 6 cyl. cars could have only one pipe behind rear wheels. But who knows, I've seen "7X" cars with two pipes exiting on the right side before the rear wheels.
  • From other reading I have run across the issue of those using the Clifford Headers not having enough heat in the carborators for the car to run well at lower tempatures. Anyone have any first hand experience with that? I want to ensure I can have the car out from the first of spring until at least thanksgiving.
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