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1962 AC Bristol: The Grasshopper
That is quite an LA point of view. The prevailing view here tends to be that a car is a bit like a suit of clothes. A garaged and lightly driven car lasts and holds its appearance for decades. Because cars last so long in this weather, people may have two or more for different occasions. With a car like an AC Bristol, well, that is quite a statement, anywhere, but especially here in LA.
Thanks so much for showing us your car. Your AC Bristol is so significant as a transitional design, much of which was used without alteration by Shelby, for his Cobra. That car, by the way, Cobra #1 is going on display at the Peterson Museum, opening February 22. The suspension with transverse leaf springs, and the innovative subframe tying engine and differential into one piece, were so effective, that initially Shelby did not make any changes to the configuration. The 260ci V8 was installed in an engineless AC Ace, and the car was tested on the track.
Here is some background material on the car. Apparently this is an “AC Ace” in “Bristol Specification” with Bristol being the engine builder. Apparently 686 such cars were built. From the attached article: “In 1956, the highly regarded 1,971-cc Bristol six became available, upgrading the standard Ace to Ace-Bristol specification. This high-revving, state-of-the-art power unit initially produced 125 bhp at 5,750 rpm, which rose to 128 hp in its ultimate D2 specification, care of increased compression from 8.5:1 to 9:1. The engine could trace its origins back to BMW’s advanced pre-war 328 design, which helped make it successful in racing well into the 1960s.” https://www.hemmings.com/classifieds/cars-for-sale/ac/ace-bristol/2227006.html
Apparently the body is made from a light alloy, and not fiberglass. From some of the compound curves below the front headlights, which are easy to execute in glass, and difficult to do on an English wheel, you might think glass, but it is an aluminum alloy. Comparisons are often made between this chassis and that of a Ferrari barchetta of the time.
Apparently the Bristol 100D2 engine, in this car, a 2 liter inline six, was developed by Bristol from the BMW M328 engine that Bristol produced in England under license from BMW during the 50s. Both Bristol D2 and BMW M328’s are push rod engines w/ aluminum blocks & heads, a cross flow configuration, and hemispherical combustion chambers. Valves are overhead. https://wikivisually.com/wiki/BMW_M328.
I found an image that shows a few of the exhaust valve transverse rods. There are two rocker covers at a wide angle. This looks like a double overhead cam engine, and is not. There are two rocker shafts; one on each side. The intake shaft has rockers to drive the intake valves AND it has intermediate rockers that drive six transverse push rods, across the top of the engine block, that in turn drive rockers, on a second rocker shaft above the exhaust valves. One cam in the block. Two rocker shafts. 
The 1952 Siata 300BC Barchetta also uses the same kind of front suspension as this AC Bristol, with a transverse leaf spring being used as the upper front control arm. This provided exceedingly low unsprung weight. The AC Ace and AC Ace – Bristol use the transverse leaf spring front and back, for fully independent suspension. A layered, leaf spring is a sharply progressive rate spring. Progressive rate springs provide a great deal of chassis roll control. So sway-bars are not so necessary in these cars. These AC roadsters and the Italian barchettas of the time were on parallel development paths. Photos of the Siata suspension are available here: https://bringatrailer.com/listing/1952-siata-300bc-barchetta-sport-spider/
Hands down my favorite car of all time. I doubt i will ever own one because the values have gotten crazy. Lots of them were converted to V8’s because of the Cobra connection.
If memory serves the Bristol engine was BMW derived. So, maybe a Cobra kit car with a BMW engine? That would be close.
I would stay with a small straight six or four if you can. From a Hemming’s article about the Bristol and the Cobra: “The straight-six AC Ace-Bristol is Dave Brubeck: airy, light, jazzy, satisfying. The V-8 AC Cobra is the Rolling Stones: faster, harder, slightly indelicate, and letting you feel just a little bit dirty for having been involved.” I saw the first ‘production’ Cobra, not the prototype, but the 289 production version, this weekend at the Petersen Museum. And it is not my car. There is no way to open that thing up off a closed course.
https://www.hemmings.com/magazine/hsx/2014/03/Easy-as-ABC—Ace-Bristol-Cobra/3735601.html
