Hi all, New Australian member here

I have recently started doing the engine on my 1961 Oldsmobile 98 'Sport Sedan" and wan to change the "2 manifolds to 1 pipe" set up and put a true dual exhaust system on her.
I am hoping I am able to get some ideas and direction to a set of manifolds that will fit.

I was told that a LHS 403 manifold will fit. But am unsure.
I was going to put the manifolds on the opposite sides and cap the port on the 1 side, but that manifold will foul on the steering box.

If there are a ser of extractors out there I would be keen to hear of them and hope that the seller will post/freight to Australia.

I will attach a couple of pics of my current exhaust,

CHeers,
Shaun

 

Welcome. The first gen Olds V8 motor share pretty much nothing with the second gen designs. A 403 manifold will not even be close to fitting a 394. The factory parts book shows the same manifolds used for both single and dual exhaust on the 1961-62 394. The factory simply installed a cap over the extra crossover port on the RH manifold.

 

 

Hi Shawn and welcome mate, another Old's down under on the Gold Coast by the look of your pic.
Cant help with your exhaust issue, but we would all like to see some pics of your '61 Old's 98. Is it LHD still, or has a RHD conversion been done?
I haven't found many useful parts here in Oz for these cars, I've had to import $$$'s worth of parts myself and shipping is sometimes more than the parts cost, even went to the U.S last year with empty bags and brought back a swag of parts in my luggage!

 

 

real nice car shawn lovin' the two tone, looks to be in decent shape too.

 

I also wondered about clearing the steering box, but here's the page from the Dec 1961 parts book with the April 1962 update. It only shows P/N 579279 as the LH manifold for all 1961-62 394 motors.

 

So I need to find this 3.609 "Front pipe"?
I would hope it would clear and not foul on either the pitman arm and seering box.

Where would I find this part code, so I can begin looking?

 

It is in pretty decent shape...... Tho the rust in the RHF floor and fender needs addressing. None of the electric options work neither.

I have not yer found a floor panel that isn't going to cost me $230AUD to send here to australia either lol

 

3.609 is just the group number for a class of parts. The actual part number for the pipe is shown in the table below - 581537 (D.E. = dual exhaust). You are highly unlikely to find one. These have been out of production for over half a century. You may find an exhaust vendor who offers reproductions of the original pipes, or you will have to have one custom bent by an exhaust shop or welded up from mandrel bend sections.

 

Joe is correct, that dual exhaust manifold is as rare as hen's teeth... here in the US. I owned a 64 98 many yars ago and I never ran across a driver's side dual exhaust manifold for it. Your best bet is to find an exhaust shop that can make you a set of custom headers. At least that way you won't have to pay big money for shipping.

FWIW, here is the manufacturer that reproduces later model Olds exhaust manifolds. I don't know if they've ever considered doing the dual exhaust manifolds for the 394. There's probably not much demand for a reproduction like that.

https://www.themotorcompany.com/home.php?cat=108

BTW, that is an AWESOME car. Welcome to the site and good luck with your project.

 

Just to be clear, the OP has a 1961. The parts book does NOT show a separate dual exhaust manifold for the 1961-62 cars, only for the 63-64 cars.

 

The 63/64 dual exhaust manifold does work on a 62 full size car, I can't see any reason it shouldn't work on a 61. I have used this manifold on my 62's. (starfire and wagon) without any interference with the transmission or starter motor.
You will find these manifolds are becoming more scarce as the Starfire people with 62's and I guess 61's are buying them up.
When I added the L/H dual exhaust manifold to my car I sold the original pipe to a member here to add dual to his 62 88.
The pipe section Joe is showing I've seen for sale in the past on Evil-Bay and several years ago at the Nationals meet.
This manifold was available on the Starfire and the 98 custom sport coupe, you could also special order this when you ordered your car at the dealer.
Steve

 

Joe and Steve are both correct. The 61-62 full-size car uses same LH exhaust manifold for both single and dual exhaust. 63-64 full-size dual exhaust has a separate part number and it can be successfully used on 61-62 IF you can find one. It does get the exhaust out of the steering.

They are used on all 1963-64 Starfires and Ninety Eight Custom Sports Coupes, all 1964 Jetstar I's (not Jetstar 88), and were optional on all Dynamic and Super 88s and non-CSC Ninety Eights.

Nice Sport Sedan by the way. An uncle had one and they bought it late in 1961, and then drove it from Virginia to Washington state for the 1962 Seattle World's Fair. At one time we had a pic of the car with the Space Needle in the background.

 

But the point is, you don't have to. The factory built dual exhaust cars in 1961-62 using the manifold that the OP already has.

 

The original post the OP asks about changing manifolds not adding a pipe, I agree that 61 and 62 used the same manifold for both exhaust systems. The 403 exhaust manifolds don't fit therefore he should be trying to find the correct manifold. The pipe addition from single to dual is an option he might look into and most likely will be his only option until his search for the Holy Grail of manifolds becomes available.

 

The OP asked about changing manifolds because he incorrectly thought he needed to do that to convert to dual exhaust.

 

Shawn I put dual exhaust on my 61 Dynamic 88. I bought a kit off of Ebay for $400 shipped. I ended up using Cherry Bombs for the mufflers at the rear where the factory resonator was. The pipes fit up in the rear wheel well which I don't like but that's the way they were bent. I didn't use the mufflers included with the kit because the ends were welded on and when i tucked the pipes up in the wheel well next to the frame for tire clearance it put the mufflers at a weird angle. In retrospect i probably should have taken it to a local shop I was quoted $600 and after the $400 for the kit plus buying different mufflers plus the time laying on my back i would say that is a good deal. I would get a quote from a local shop if you can. Take the factory manual with you to show them what it looks like and how it is routed. The kit i bought was bent off of factory drawings supposedly and it did fit good besides the muffler issue.

Oh, and yes you only need to block off the front of the passenger side exhaust and you can use your existing drivers side manifold.

https://www.ebay.com/itm/1961-OLDSMO...item590734f4b5

^This is the outfit i bought the exhaust from. It is a good kit for the do it yourselfer. I think it sounds great with the Cherry Bombs.

BTW to me there are multiple benefits from the duals. More power, better mileage, sounds better and it gets rid of the crossover pipe right under the oil pan which i hated.

 

You might try Waldron Exhaust. They made all the pipes for duals on my 54 and it fit. The left side is a challenge with power steering but it worked.

 

 

https://classicoldsmobile.com/g/album/5513930

https://classicoldsmobile.com/g/album/7666316

Thanks Shaun, awesome 61 dude. Great interior, with factory air!

 

 

Shaun, if you are going to use the factory AC components on your Olds I suggest either charging the systeme with original r12 or using a replacement like r12a.



It's a refrigerant that's available in Canada that I used to charge the r12 system in my 86 f250. It works great.

I don't suggest using r134a in an r12 system. I updated the r12 system to r134a in a 1990 Buick Estate wagon I owned. I did everything by the book (i.e. flushing the system, replacing the drier, hoses and orifice tube, etc.); unfortunately, it never cooled quite well.

Of course, Vintage Air or other aftermarket AC systems are an option too. Let us know what you decide to do.