Its called Cruisin on Main and is held on Main St. in Manchester CT. Its one of the best shows I have been too (and it helps that I live about 10mins away). There are tons of cars, most of them are American iron though so if you are big into the European scene you may be disappointed. I would say there is probably a mile and a half jam packed with cars (which again are mostly 60's muscle).
In any event, there are alot of really neat cars and people that show up. Manchester Motor Car is another sponsor and they bring lots of really cool stuff of all vintages.
As said the viewing is free, the event is "sponsored" by DRC FM which is our local 60's and 70's station. The registration fee is only $5. This year I'm trying to get my dad to bring his 911 and my buddy is trying to get a Pantera to join us . . . the benefit of showing a car is that you get in earlier.
If you don't bring a car to show out of towners usually end up parking on the sides of 384 and down Hartford Rd (which runs perpendicular to Main St). If you are going to go you have to show up at 1pm . . . there's just so much to see.
For any more details go to
http://www.cruisinonmainstreet.org/
aug 6 in manchester,ct. over 2,500 cars MINE INCLUDED AND 35,000+ PEOPLE it is the largest one day car show in new england... maybe we should have a 914 showing!!! jim kelly in mass where are you?? how about eric?? chris???anyone!!! 
oh 1-5 reg is 5.00 and to look is FREE~~~~~