However, I'm not such a traditionalist!!
Something like a CRX engine (and fabulous they are too) would be a good choice, but you have to ask yourself if it's worth it for several reasons:
Get the conversion done badly and it'll run worse than any Fiat and leave you stranded when you least expect it. A swap like that is a really big job and needs to be done by a professional who really knows what he's doing if it's gonna run right. This is gonna cost BIG bucks.
Big power in an old car is a bad idea unless the chassis is made capable of handling it. Old cars do not drive like new ones, and a half hearted conversion could leave you with an expensive motor that likes nothing more than to do pirhouettes at the slightest hint of rain, or has way more power than the brakes and handling are capable of dealing with. Chassis bracing would probably be a good idea, as the existing one would probably flex quite a lot with decent power and cause rather, er, 'unexpected' traits.
A quote that I remember from years back: old sports cars are beautiful machines, but the reality sadly never meets the expectations of drivers of modern cars.
If done right, it should produce a brilliant drive - especially with a nice revvy vtec motor. If done wrong, it will be a horrific waste of cash that you'll curse every day and it might well polish you off. If you have the cash to have it done RIGHT, go for it!!!
Pete.
Cinq sporting 1242cc
http://mysite.freeserve.com/close_to_cracking_up/