Its interesting (to me anyway) to see the responses here. I am also in the process of building a Locost (Lotus) 7 replica. These cars have been around since 1959 when Colin Chapman wanted to put a high performance car within reach of the "average Joe".
On the Locost 7 site guys are installing all kinds of engines in their cars, BBC, SBC, BMW, Miata, BBF, SBF, Rotary, Mazda, Toyota, Motorcycle motors and anything else you can imagine. One guy is installing a V12 Jag motor!
The original cars started with British Leyland motors and then switched to European Ford 4 cyl motors and finally a Ford/Cosworth headed 4 cyl from the factory.
I am personally installing a BL (MGB) motor for a "period" take, plus the engine/trans were given to me for free.
The interesting thing to watch on that site is the amount of support and cheering whenever someone new comes aboard with a new take on how to build their vision.
And talk about performance! These cars end up under 1400 lbs with a SBC or SBF motors. Some have the original type live rear axle/unequal length front suspension. Others have more exotic IRS and race style inboard coilover shocks on both ends. They are killer autocross cars. One guy is building a BBC alloy motor car in his penthouse apartment In Canada! Quite a site to see his photos. They are also road racing at some tracks in all sorts of classes.
Bottom line, they all embrace what everyone is doing. Because they can!
Thom