Don't get me wrong - it'd be a great project but it depends on your budget and what you actually want out of the car. How much are you looking to spend?
The thing is that you can buy a good, solid, usable C3 for about 5.5k - and a really great example for about 8 (I'm not talking any of the early desireable ones here necessarily, more the later 70's onwards smogged models).
What kind of car are you looking for in terms of condition? A complete shed or something usable already?
Examples of cars you could pretty much just buy and use:
http://cgi.ebay.co.uk/CHEVROLET-CHEVY-C3-CORVETTE-STINGRAY-/190433931489
http://cgi.ebay.co.uk/CHEVROLET-CORVETTE-C3-1980-/230513590921
Best till last :
http://cgi.ebay.co.uk/CORVETTE-L82-C3-/160469723882
Problem with the '75s (the C3 generation in general) as well is restoration can be quite a costly (and involved) task. Parts are not necessarily cheap and suppliers are thinner on the ground here for them, meaning a lot of stuff will either carry a premium, or take time to arrive. Trim and rubber components can be expensive and on a restoration project that'll be the majority of stuff that's damaged or missing. Areas of them can also be trickier to work on.
Base '75 models, like JRS says, only run about 165BHP with a cat (although around 300/320ft.lb).
They have plastic composite bodywork which generally requires professional prepping and painting, suffers from cracks and can be hard to get right if damaged. The chassis is simple and easily repaired but the suspension and steering are usually shot on 'restoration' projects and those are not only time consuming, but potentially expensive, to get right.
The powertrain itself is usually unburstable though but many have been abused, or just left unserviced.
Of course, all this stuff can be dealt with in your own time but it's worth thinking about if there are aspects you don't want to get involved in.
Again, as JRS notes, a C4 is a much more modern car, in terms of both ride, performance, handling and refinement but equally it's a very different beast
(Although an early one with a Crossfire engine isn't far off a late 80s C3, barring shape)! A C4 is also infinitely more easy to work on and less prone to faults, especially on a daily basis - but as mentioned, the C3 is a bone-fide classic muscle car shape whereas the C4 is something else.
Even the old bone stock '84 (the lowest powered version) Crossfire C4 will do 60 in 7 seconds, where as an 80s C3 will only do it in around 8 - although there were faster variants available. A '74 with 195BHP will still do 60 in under 7 seconds due to their weight and gearing so still pretty damn lively.....
Such a lovely looking car. 
