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exhaust manifolds / headers for a '68 cutlass convertible


Chet44

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I have a '68 Cutlas Convertible I am in the process of restoring. The problem I am having is this: I dropped a 455ci V8 in it, and now I can't find any exhaust manifolds or even headers for it. All of the exhaust manifolds i can find for the 455 specifically say they will fit everything but a convertible. I suspect this is becaust the convertible has a boxed frame, while the hardtops do not. Anyone out there know where I could find manifolds or even headders for this? Thanks in advance,

Chet

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<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Chet44</div><div class="ubbcode-body">I have a '68 Cutlas Convertible I am in the process of restoring. The problem I am having is this: I dropped a 455ci V8 in it, and now I can't find any exhaust manifolds or even headers for it. All of the exhaust manifolds i can find for the 455 specifically say they will fit everything but a convertible. I suspect this is becaust the convertible has a boxed frame, while the hardtops do not. Anyone out there know where I could find manifolds or even headders for this? Thanks in advance,

Chet </div></div>

There is absolutely no difference between the hardtop and convertible frames forward of the firewall. Use the headers or manifolds for a 442 hardtop. This has been a frustration for years. There is bad info that the header manufacturers simply repeat without verification.

As for manifolds, the factory installed big blocks in the convertibles, so the factory manifolds for an A-body work fine. The 69-72 W/Z manifolds flow better than the 1968 X/Y manifolds due to the separate internal runners, so I'd use those. By the way, there were ABSOLUTELY used on the 1969 442 convertibles from the factory, so I don't understand why you say you can't find manifolds.

Any header that fits a big block Olds in a 68-72 A-body frame work fine in the convertibles (AND the Cutlass Supreme, by the way). ANY Olds header will require you to relocate the brake distribution block on the LH frame rail. This is not related to it being a convertible. All headers will also be tight around the starter.

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There was also supposed to be an issue with special big block Dodge Dart GTS and Formula S Barracuda exhaust manifolds. There were special driver side manifolds made that were pinched down to clear the steering column. It took away 35 horses from the engine. In actuality, they did not need to be pinched because the standard magnum manifold fits. You might have to move the steering column over as far as the adjustment would allow, but they would fit. Perhaps this is the same issue with your car.

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<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: keiser31</div><div class="ubbcode-body"> Perhaps this is the same issue with your car. </div></div>

It's not. Again, Olds used EXACTLY the same mainfolds, by part number, on hardtops, convertibles, four doors, and wagons.

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