[Aussie Mike]

The bottom end would probably be fine with the technology that is readily available but the heads would need a serious redesign to meet the current emissions regs.

I reckon with the use of twin turbos and EFI with Propane fuel (LPG) you could build an FE that would make more power than you know what to do with and produce clean emissions. Propane is a fairly clean fuel and the twin turbos actually help with emissions because they let you run cam with less overlap and their intense exhaust heat burns off a lot of the hydrocarbon emissions. Stick a pair of cats on there as well and it'll be just daisies and baby's breath that comes out of the exhaust.

The problem with Propane is the tank required to get any kind of decent range is going to fill up your whole trunk.

Cheers