300-400 is a good price.
They are going up in value as they are becoming "classic" instead of just "old".
The only problem is if the panels have significant rust (can't get new panels) or if the trim has perished (also not available).
All mechanical parts are easily repaired, replaced or upgraded (mine has bits from 1970 to 1985).
The 3S-GTE can certainly go into the 77 Celica but it's not trivial.
If this is your first engine swap then you would be better off choosing a simpler swap.
I'd recommend a 22R because it is a very easy swap.
An 18R-G twincam is a little more adventurous (mostly finding parts) but this is what they came with in Japan and is what I have in my '77 liftback.
Here is a list of other possible swaps:
http://ourworld.compuserve.com/homep...pho/celfaq.txt
Fuel tank:
This might be a problem.
You could take it to a fuel tank specialist and ask them if it can be chemically cleaned inside to get rid of the rust.
If it is too far gone then you may have to get a new tank made up.
Most race cars have new safety tanks made up, so there will be plenty of companies able to do it.
Hopefully one of them will do it for a reasonable price.
Is it the '77 coupe (RA24) or the '77 liftback (RA29)?
More help is available at
http://autos.groups.yahoo.com/group/...elica/messages
- Stepho ('77 liftback, Australian spec RA28)
http://ourworld.compuserve.com/homep...ho/celprod.htm