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Just found that the passenger side Manifold is cracked. Was looking into Thornton's 350 Jr manifolds, so we can add a true dual exhaust. They mention they fit olds 350 cutlass and some other vehicles, but not the Omega. The drivers side manifold is close to the steering box. Will the Thorntons fit ? I have a 1973 oldsmobile omega with a 350.
Was looking into Thornton's 350 Jr manifolds, so we can add a true dual exhaust.
Just out of curiosity, why do you think you need an aftermarket manifold to run "true dual exhaust"? Even the W-31s used the stock manifolds with the cap and ran "true" dual exhaust. FYI, the 73-74 Omegas with Olds 350 use 411961 LH manifold and 411962 RH. That LH manifold is the same one used on 70-up 350 motors in A-body cars. The RH is unique to the Omega.
Thanks Joe. Were can I find these manifolds than. I have searched but could only find the aftermarket ones. Thanks.
Unfortunately, good used will be your only option. The LH is easy, since it's the same on A-body cars. The RH is the problem since it is 73-74 Omega only. Sorry that's not particularly helpful. I know Hooker used to make headers for this application - P/N 3104.
Post a pic of the driver side. The outlet angle on the passenger side is different but will work. If the driver side is unique, there will be a packaging reason.
Does anyone know if the Thornton Manifolds will work on the 73 oldsmobile omega with a 350. What makes the RH manifold different?
While again, not firm proof, you can be sure that if an A-body manifold would have fit, Olds would not have tooled up for a unique manifold for a single model for two years only. Obviously they DID use the A-body manifold on the LH side where it worked. The Thornton manifolds are designed to fit the A-body.
It's hard to tell from the angle of your photo, but it appears that the outlet on your RH manifold has more of a 90 deg turn that do the outlets on other SBO RH manifolds.
As I said the Thorntons simply mimic the shape of the A-body manifolds, so same problem, apparently.
Post a pic of the driver side. The outlet angle on the passenger side is different but will work. If the driver side is unique, there will be a packaging reason.
From above:
Originally Posted by joe_padavano
FYI, the 73-74 Omegas with Olds 350 use 411961 LH manifold and 411962 RH. That LH manifold is the same one used on 70-up 350 motors in A-body cars. The RH is unique to the Omega.
From the photo of the OP's passenger side, the A-body manifold outlet will run the exhaust pipe right into the firewall. If you REALLY think it will work, I'd suggest trying a cheap used A-body manifold BEFORE shelling out big bucks for the Thorntons.
Here is a picture of the drivers side. not a good view but they look the same as thorntons. I also included a photo of the measurment from the last bolt to the downturn of the manifold. Does anyone have Thorntons could measure the passenger side manifold from the last mounting bolt to the beginning of the downturn. Drivers side Distance from mount bolt to downturn
Here is a picture of the drivers side. not a good view but they look the same as thorntons.
Look again. Your manifold appears to have nearly a 90 deg bend downward, and the mating exhaust pipe has a matching near 90 deg bend upward. The A-body RH manifolds have closer to a 45 deg downward bend, which means the exhaust pipe hits the bottom of the firewall. You seem to have your heart set on the Thorntons. Your money, your risk. Again, I would STRONGLY suggest that you get a cheap or free A-body manifold and try it first. That's about the limit of help I can provide.
Joe, I appreciate your information, but I understand the difference from the Thorntons to the Stock and that the stock has a 90 degree vs a 25-45 degree on the Thorntons, That's why I asked if anyone has them installed and can measure for me to see if the length before the bend would fit in my Omega. The firewall is angled at that point so if the degree of the bend is correct, and there is clearance before the firewall, the Shop I had the exhaust install at can bend to match that angle. Please don't assume that someone is bent on something, Im gathering information to make the best decision for us.
You can probably trim the firewall lip to clear the manifold. Getting a manifold to test fit isn't a bad idea. I personally would get their shorties over their manifold's. They should fit where your manifold 's fit, it does look tight to the steering box. https://s3.amazonaws.com/sites-thorn...4/s-l500-2.jpg
Last edited by olds 307 and 403; January 26th, 2019 at 11:44 AM.
I'm going to install the new RH Exhaust Manifold this weekend. I read someplace that they did not use a gasket from the factory. Is this correct . If so Do I just install it again the same way? Do I put it on dry or use Sealant? Or should I use a gasket and what type is recommended.
It looked for 3 days for the part and finally a Sales Rep for Fusick Automotive Products gave me a LInk to search nationwide for used car parts. What great service . I found the correct 73 RH exhaust manifold for the Omega at Hidden Valley Auto Parts in Arizona.
Glad to see you found one. They must be getting scarce. Unfortunately, most probably end up in the crusher without anyone realizing the uniqueness of the exhaust manifold.
Since your on the subject, I'm replacing dual exhaust system complete & I had a question about the Thornton Exhaust manifold are they a bolt up aka turn key installation on my 1964 olds cutlass 330 4v?
And the biggest question they are 2 1/4" outlets I've never seen a 2 1/4" exhaust pipes for this car they are 2 1/2 or 3
Also does any exhaust manufacturer make replicas of the 64 exhaust the tailpipes have the bend over the rear end then they bent/flare out to the sides & out points to ground + if your looking at the trunk/rear bumper you can just see them at each end of the bumper what I've seen is most go straight back like straight pipes coming out the back like middle of bumper don't want them that way want then original
Since your on the subject, I'm replacing dual exhaust system complete & I had a question about the Thornton Exhaust manifold are they a bolt up aka turn key installation on my 1964 olds cutlass 330 4v?
And the biggest question they are 2 1/4" outlets I've never seen a 2 1/4" exhaust pipes for this car they are 2 1/2 or 3
Also does any exhaust manufacturer make replicas of the 64 exhaust the tailpipes have the bend over the rear end then they bent/flare out to the sides & out points to ground + if your looking at the trunk/rear bumper you can just see them at each end of the bumper what I've seen is most go straight back like straight pipes coming out the back like middle of bumper don't want them that way want then original
Hi,
I had a set on my 65 Cutlass with a 330, to replace my broken original manifolds. Ran 2-1/4" pipes no issues, I also ran 442 chamber tailpipes, made by Walt who retired the business to my knowledge, believe Gardner makes a kit for the 442's/bbo, not sure how the headpipes line up but believe they are the only one's making the tailpipes.
Thanks for the info it helps, the 330 motor in the 64 engine compartment has a comfortable amount of room just wanted to use manifolds that create problems rather then solve them
January 25th, 2019, 06:08 PM
