I have posted this same question on the eldorado/seville forum..apologies if thats a bad thing...i wasnt sure ..anyway:
Hi, i live in england...my daily driver is a 1970 500ci fwd eldorado,
It currently gets around 7mpg in town (havent taken it on higway yet as its waiting for new front end rubbers)
I had planned to add an LPG (liquid petroleum gas) conversion to save money on fuel bills. Lpg is approx half the price of petrol so that would make my eldo the equivalent of 14 mpg in town....in my opinion thats better but still outrageously expensive in the uk-(petrol is aprox £1.10 and lpg is approx £0.60 sterling). My ideal target would be 20 in town 30 on highway... Yeah i know!!
Here is my crazy question...
Has anyone ever swapped the 8.2 V8 for a smaller/better fuel economy engine...maybe another more modern caddy block or even a diesel truck engine? This is a huge hypothetical question but i am serious in keeping this car and using it every day i'd sleep in it if my wife wouldnt mind! If it were doable i would want to keep the original engine nice and safe in storage just in case...some of you MUST have considered this.
Brace yourself matey, you're probably going to get some serious ribbing, you know
Diesel -- GM did have a go at diesel cars in 80's, but weren't very successful, in part for reliability issues
The car weighs over 4,600 lb so there's more to fuel economy than just the large engine, though if you remove it you'd probably lighten the car by 500 lb at least (then maybe it could be towed by a team of donkeys?)
seriously, I think an electric conversion could be a good answer -- you could probably get it done for about the same money as an engine swap, and it would be more economical to operate. lots of capacity for batteries too!