Independent Plymouth
Q. What's the best way to put a Jag front and rear suspension under a '36 Plymouth coupe?
Charles Morse
Via E-mail
A. An improvement over the '35 Plymouth, the '36 has boxed chassis 'rails and a substantial riveted X-member, making it sturdy enough to remain as the basis for an upgrade in the suspension department. Before we go into how to mount the Jaguar components, we should mention a few things. Try to avoid using an XJ40 (the later, squarer Jag with rectangular headlights) as a donor car, especially if you want to run 15-inch wheels, as they use 16-inch wheels, and the large front rotors and calipers won't allow fitment of smaller-diameter rims. Early Series 1 XJ components should also be avoided, as they use solid brake rotors. If you can find a late Series II or early Series III XJ, these have vented rotors and four-piston calipers. Series II cars were manufactured from 1973-79 with the Series III taking over in 1979 until 1988. Incidentally, the front spring rates are the same for six- and 12-cylinder cars, and are perfectly acceptable if you're planning on installing a small-block or similarweight motor, but you'll have to install higher-rated springs if you're fitting a big-block.
Mounting a Jaguar rearend can be done in one of two ways, either using the stock "cage" the unit is mounted in, or doing away with this and fabricating a crossmember from which to hang the differential and coilover shocks. This is the option we'd go for (and you could do worse than check out our IRS feature in the February 2008 R&C for caged and uncaged Jag rears to get an idea of how they look). The independent front suspension can be used complete with its crossmember, which has a reasonably flat upper surface perfect for welding to the underside of your Plymouth's chassis 'rails, assuming the ride height works out for you. (You may have to kick up the 'rails at the front.) You can mount the IFS using the stock rubber mounts, though the installation will be neater and firmer if welded in place, and you won't have to fabricate the necessary brackets. Obviously take plenty of front-to-rear, side-to-side, and diagonal measurements before welding suspension components to your frame, or you'll encounter alignment and handling issues later on.
You should also know that the Jag uses a "floating" steering rack and a sort of sliding universal joint to connect to the column. A smaller Range Rover U-joint will fit the Jag's steering rack splines for improved header clearance, but you must solid-mount the rack if you go this route. One other thing: Your Plymouth's track measures 56 1/16 inches in front and 58 3/16 in the rear. A Series III Jag measures 56 inches in front and 57 in the rear, a near perfect match, while a Series II compares at 58 in front and 58 5/8 in the rear. We'd go for a Series III donor car, considering the track width and the fact that it'll be some years newer than the Series II, and the rearends are expensive to rebuild.
Top Tip
Q. Where can I find front latches for my Carson top?
Don Barabe
Via E-mail
A. We don't know what Carson used for latches back in the day, but you can bet they were some form of OEM latch. You also don't say whether yours is a genuine Carson top or a new top built in that style. If it's not an original, you have a couple of options. We've used the small and relatively unobtrusive front latches from convertible VW Bugs before for Carson-type tops, while our pal, Brad Masterson, tells us Bill Hines uses T-top latches from Corvettes on this type of roof. They are adjustable and simply require a small mounting pad be fabricated on the windshield header. Any Corvette specialist should be able to help you.
Eldorado Rubber
Q. Can you point me in the right direction for custom whitewall tires for my 1955 Cadillac Eldorado? The tire size is 275/60/15. I have struggled for years to find what I want for my ride and need these tires so it can be finished.
Vince, The Cadillac Kid
Via E-mail
A. You're in luck, Vince, as Diamond Back Classics can supply wide whitewall radial tires in almost any size, and the company's T-4 60-Series includes the world's only wide white 275/60/15 tire, rated to 118 mph and manufactured by Yokohama. In fact, the company can even fit you out with a wide whitewall 295/50/15, should you want to go even wider and lower! For more information, contact Diamond Back Classics, located in South Carolina, at (888) 922-1642, or www.widewhitewalltires.com. Let's see that Caddy finished now!