|The MGA With An Attitude
FRONT SWAY BAR - Introduction -- FS-101
FS-101 is a short course in the advantages of installation of a front sway bar (or technically anti-sway bar). I have had some experience in this area (extensive experience actually). Check here for kicks.
I'll give you the summary first. A 5/8" sway bar is about right for the original type bias ply nylon tires, but if you don't mind driving on those crappy tires, why bother with a sway bar?
For modern radial ply street tires with a little better grip, a 3/4" sway bar is just the berries. This reduces body roll considerably, improves steering response in a big way, and keeps both rear tires on the pavement (except in a couple of very extreme manuvers). If you are keen on good handling, serious about spirited driving through the twisties, and might enter an autocross event occasionally, you need the 3/4" front sway bar.
If you should ever get serious about competition driving, and also cough up the big money for stronger wheels and some sticky road racing tires, then you would do well to install a 7/8" front sway bar, which is about 80% stiffer than the 3/4" bar. The race tires would have grip far superior to the street tires, would cause much higher cornering loads, more body roll force, and greater left to right weight transfer during cornering. The result is what you see in the picture from the web link near the top of this page. With the sticky tires and the 3/4" bar the car can still lift the rear wheel in a hard turn. With half the weight of the car on one rear tire it loses grip efficiency with that tire, and the rear end will let loose and slide out causing nasty oversteer, which is not good for handling or speed, and can actually be dangerous on the highway. The 7/8" bar will will keep the rear wheel down when using race tires, which will avoid the oversteer problem. The flip side is that when using the 7/8" bar with street tires it will be a little twitchy in the steering (if you're not used to it), and the ride will be a little harsher on a rough road (but not much different on most paved roads). I love my 7/8" sway bar, because I compete on race tires regularly, but otherwise I wouldn't recommend it for use with regular street tires.
Never install a rear sway bar on a MGA or a chrome bumper MGB. That would just aggrevate the problem of rear wheel lift and severe oversteer. The problem there is that the original rear leaf springs are quite stiff, so the rear suspension already has more than enough roll stiffness. Installing a rear sway bar only serves to lift the inside rear wheel sooner and higher, aggrevating the oversteer problem in a fast turn.
Also be careful about installing new rear springs on the MGA (and maybe also the MGB). New leaf springs available in recent years have commonly been fabricated with too much arch so the car sits an inch to an inch and a half too high in the back. This causes the rebound straps to run out of travel quickly with only moderate body roll. When the strap hits the end of travel it lifts the inside rear wheel off the ground and causes the same nasty overster problem. I had new rear springs on my MGA for the Alaska trip in 1997, but shortly thereafter I reinstalled the original springs.
Getting back to the front end, the original type front sway bar on the MGA requires the indentations in the top of the front frame extension for mounting. This frame part was only intruduced with late production MGAs. Earlier cars may need a replacement front frame extension to accept the sway bar mount (or some cut and weld mods to the frame). Also, many of the currently available mounting kits do not include the correct original type frame mount brackets for the bar, so you may have to do a little cutting to notch the inner fenders to clear the new bar. And the original type sway bar mounts on top of the front frame extension, so unless the body is off the car you would have to remove the front bumper, the front valance panel, the horn(s), and the front frame extension in order to install the sway bar. The original type links also require the later type spring pan and front a-arm bracket with the (reinforced) hole to accept the link.
Aftermarket sway bars will commonly bolt to the bottom of the front frame extension (see FS-102). These usually have links that are essentially a straight bolt with grommets and cup washers like the rod end of a telescopic shock absorber. These links are available through any local auto parts store. This type of sway bar is easy to mount, and you don't have to remove anything (except maybe the horn).
For spirited driving and long term durability I can also personally recommend using the polyurethane bushings for both the frame mount and the end links. V.B. sells these parts separately from the sway bar kit (added cost). You can also buy them through J.C. Whitney for half the cost. And you may be able to order the sway bar kit with the polyurethane bushings included as original parts.
One last word here. If you lower the suspension height for competition driving, in general you will need less stiffness in the sway bars, or you might actually find some benefit from a small rear sway bar in combination with a large front sway bar. Fine tuning from there is up to you.
Have fun tinkering, and then have WAY more fun driving. And remember, attitude is contagious.