simpleold

Can somebody point me in the right direction I understand Thornton sells different exhaust manifolds, i need to put dual exhaust on my delta 88 1969 455 engine what are the correct part numbers driver side and passenger side manifolds i need to use? are they bolt ons? I'm a bit confused with y,Z, w, and i believe s manifold, can someone clarify exactly what i need for my 1969 Oldsmobile delta 88 455 to have dual exhaust thank you

Oldsmaniac

S manifold for driver's side the rt side uses the same manifold you already have. The crossover port gets capped. This is what the factory did.

joe_padavano

The Y, W, Z manifolds are for the A-body cars. Your Delta requires the "S" manifold on the driver's side and a cap on the second port on your current passenger side manifold. Note that the repro caps sold for the Olds 350 manifolds do not fit the 455 manifold. You will need to fabricate one by cutting the flare off the crossover pipe and welding a plate across it. Also note that unlike the A-body manifolds, these full size car manifolds DO use donuts to seal to the exhaust pipes. The correct ones are no longer sold, so you will have to find the closest fit currently available from Walker. It does not fit tightly into the opening. Use Walker Acousti/Seal (P/N 35959) to help seal them.

simpleold

what if i use this and dont replace the manifolds is that possible has anyone use this?
http://www.ebay.com/itm/1964-77-Olds...BXUbiJ&vxp=mtr

joe_padavano

Did you not read what I just posted above?

One more time. To run dual exhaust on a 1965-1970 full size Olds, you MUST use the correct driver's side manifold. You CANNOT use the single exhaust manifold on that side - the pipe will not clear the steering box and starter. You MUST use the existing passenger side manifold and fabricate a cap for the second port.

simpleold

got it sorry i guess i was going cheap thanks again for all your fast input

simpleold

Wanted to share how the S W Thornton exhaust manifolds look installed, will soon install and h pipe and dual flowmaster 10 Im still debating on which mufflers though, right now running open exhaust I just wanted to shared this video as I never found actual pictures of how the S W Thornton exhaust manifolds look after installing them on a 1969 Oldsmobile delta 88 455, YouTube video link attached

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