1958 Convertible Cowl Shake

Hello Bill,
I have a 1958 Lincoln convertible and have serious cowl shake between 35 and 45 MPH. The car runs smoothly at low speeds and high speeds but the shake begins at 30 MPH and ends at 50 MPH. The car is fully restored and everything is adjusted to factory specifications. The car runs perfectly straight and smooth at 100 MPH. My Lincoln is an early 1958 production unit and does not have the engine compartment braces. Would installing these braces eliminate the cowl shake? Is there anything else I could do to eliminate or reduce the cowl shake? It is very annoying and makes for an unpleasant ride because most of my driving happens to be in the 30 to 50 MPH speed range where the cowl shake is at its worst. By the way I am also missing the front underside corrugated steel reinforcing plate located near the rear of the transmission. Could this be causing the cowl shake? Thank you very much for any help that you can provide.
JNT
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JNT –
The kind of cowl shaking and shuttering etc. that you are describing can really make for an unpleasant ride in a fine luxury car such as a 1958 Lincoln Convertible. I fully understand your desire to eliminate as much of this as possible. You mention that “everything is adjusted to factory specifications” so I will assume that the tires and wheels as well as the driveshaft etc. are in balance. I also will trust that there are no loose panels or doors etc.
This series of Lincolns and Marks underwent many, many running changes during their years of production. It is no secret to us Lincoln and FoMoCo lovers that the factory engineers at Wixom were scrambling especially during the months following the 1958 introduction to eliminate the structural problems in order to improve the cars overall performance, handling and ride characteristics. Therefore I agree with you completely that any bracing, dampening or isolating features that were installed on later production vehicles would somewhat improve or eliminate many of the above annoyances that you are experiencing at this time. Chris Dunn has advised me also that some of the early production models – will likely continue to experience some of these issues, even if modified. I would seek out any of these “factory fix ” items that can be located and have them retrofitted to my Lincoln. If you like, we at Lincoln Land will assist you in any way that we can to source out any of the required parts. Feel free to contact George or Chris here at Lincoln Land at any time for further help or advice.
Sincerely,
Bill