The Plus 8 prototype was based on a modified chassis from the Plus 4, altered to accept the Rover alloy block 215 cu in (3.5 L) V8, purchased from GM-Buick in 1967.

The 35th Anniversary model was built in 100 examples and has a walnut dashboard, mesh behind the grille bars, a "LeMans style" gear knob, and a badge on the rear panel.

This limited run forwent the traditional roof in favour of a small fly screen and hidden roll bars behind the front seats.

The prototype Plus 8 (identifiable by two small bonnet bulges near the centre bonnet hinge) used a Buick 215 V8 engine but the production Plus 8 was launched in 1968 using Rover's production engine, a re-engineered version of the Buick 215 motor (renamed the 3.5 L by Rover) with a compression of 10.5:1 originally fuelled by two SU HS6 carburettors.

With the added power, up to 204 bhp (152 kW; 207 PS), and low weight, the Plus 8 was able to best a Porsche up to 90 mph (140 km/h) according to the magazine road tests of the day.

They can draw on the ample British, American and Australian aftermarkets; these are very popular engines with easy parts or upgrades sourcing.

From 1974 to 1992, all imported Morgans (of which 98 percent were Plus 8s) to the United States were converted to run on propane as fuel to pass U.S. emissions regulations.

[citation needed] As safety regulations continue to change, Morgan was again challenged in 2006 to meet the new structural requirements announced by the NHTSA in 2000.

A request for an exemption to the law on airbags was refused and the importation of traditional (classic) Morgans ceased.