Hi all,

I am putting a dual exhaust system, (from Classic Exhaust Systems Llc), on my '72 98 which has a 455 on it. It went on pretty easy however there's a small exhaust leak on the passenger manifold - which was there to begin with and still there; (not from new exhaust). We welded the cross over pipe connection hole from the drivers' side already and that's not the issue.

Long and the short of it: I want to get another passenger side exhaust manifold so as we work on this current "leak" issue, if I need a back up, I want to have one. All that said, I'm wondering which manifolds will work. I found someone on ebay with this one, which is said to fit "67 68 69 70 71 1969 1970 1971 1972 1973 74 400 455 Oldsmobile Z Exhaust Manifold". Just hoping to confirm if this will fit my car. (I asked the seller but haven't heard back yet. Here's the whole link if helpful:

https://www.ebay.com/itm/166777425235

Thanks for any guidance.

Jay

 

1972-74 Olds full size cars with 455 and dual exhaust used casting no. 402294 on the RH side, so yes that is the correct manifold for your car. It will not be the same as your single exhaust manifold.
The correct LH manifold for your car would be 402295

 

Thanks Joe. I just want to make sure I can install this one (from the ebay link) on the RH (passenger) side of my car if needed; and it sounds like I can from what you're saying.

Not sure what you mean when you say, "it will not be the same as your single exhaust manifold". The one on the LH (drivers) side? Obviously the RH is different as it must have the added length to the manifold for the pipe to come over from the LH side... Is that what you mean?

 

Cars that came with single exhaust from the factory used a passenger side manifold that had two ports, one for the crossover and one for the exhaust pipe. Factory dual exhaust cars used 402294 on the passenger side that didn't have a crossover port. I thought you said that you had welded up the crossover previously.

 

Thanks Joe