Autodelta, the racing division of Alfa, developed a car for competition that closely resembled the roadgoing model.

Other weight reduction measures included magnesium alloy wheels, clear plastic side windows, aluminium upper control arms for the rear suspension, a magnesium valve cover, sump, timing cover and bell housing, different door handles and quarter window mechanisms, and lightweight interior trim.

The GTA 1600 did not have a brake booster and had a thicker radiator than the standard vehicle; its dry weight was approximately 1,640 pounds (740 kg).

The GTAm engine, using Lucas injection, developed 208 bhp (155 kW) at 6,500 rpm and was fitted to a GTA 1300 Junior chassis.

There are three schools of thought about the "Am" moniker, neither having ever been officially confirmed by Alfa Romeo: The car had a full steel body modified with aluminium and plastic parts.

Because of a minimum weight increase in 1971 up from 920 to 940 kg (2,030 to 2,070 lb), the GTAms had less of a need for lighter-weight aluminium and plastic parts.

The base for the GTAm was the US-market version of the 1750 GTV with a SPICA mechanical fuel injection system.

Most works and customer Autodelta cars had SPICA injection, although a different version was made for racing.

Some racing teams and private workshops also ordered parts from Autodelta and other tuners and assembled the GTAm themselves on a new or existing body shell.

In the second revised edition of the book Alleggerita (written by Tony Adriaensens, Patrick Dasse & Martin Übelher), published in 2012 by Dingwort Verlag in Germany, you will find the most complete list available of GTAms.

[citation needed] A complete and regularly updated list of the 1750 / 2000 GTAms can be found here: https://www.alfabb.com/threads/gtam-chassisnumbers.162337/page-25#post-8807697 The Giulia 1600 GTA-SA ("sovralimentato", English: supercharged) (1967–1968) was a very rare racing car of which only 10 were built.

It featured a 1570 cc twin-ignition engine with two oil-driven superchargers, and could produce up to 250 PS (180 kW; 250 hp) at 7,500 rpm.

In the USA the GTA's first racing victory was in January 1966 at the “Refrigerator Bowl”, at the now defunct Marlboro Raceway in Maryland, with Monty Winkler and Pete Van der Vate at the wheel.

The Autodelta GTA of Horst Kwech and Gaston Andrey won the under-2-litre class of the inaugural SCCA Trans-Am championship in 1966.

However, despite the GTA name, they are also generally the heaviest due to having large engines and little, if any, weight saving employed in their construction.