Actually, the 704 is what I have in the 340 in my Duster.
My 340 is a '68 that's .060" over, compression is about 9.8:1 with a set of ported 308 heads. Heads flow 264 cfm @ .500" lift and have 2.02/1.60 valves. I run it with a eddy rpm airgap intake, holley 750 DP, and doug's headers into a 2.5" dual exhaust. I have 3.55's in the car now with 26" tall rear tires and an 833 with a 3.09 first gear. My Duster is my daily driver, so, my comments about driveability are based on driving it almost everyday, freeway, traffic, all of it.
So, with that in mind, the 704 is a bit big for a daily driver. Below about 2,200 rpm with any kind of load and you risk lugging the engine, it really prefers to be above 2,200 with any kind of load (uphill, acceleration etc). Things really don't come alive until almost 3k rpm, with that cam and the 340 the car is really a lot happier if you drive it like you stole it. Cruising around town isn't really what it's set up for, so driving it more, let's say responsibly, takes a bit more clutch work on take off and between gears if you're short shifting. It needs more gear out back, and my plan is to go at least 3.91 when I get my T56 installed, although I may even go 4.10 or 4.30. I'd go to 3.91's now if it weren't for my frequent freeway driving. 3.73's with 275/60/15's will actually be like a 3.41 gear ratio compared to my 3.55's and 275/35/18's, so, if you want to run the 704 I'd plan on at least 3.91's. For a street/strip car it probably isn't an issue, but for a frequent driver the 704 is big enough to cause some driveability issues. It's doable, I mean, I do it and it works and I'm not going to downsize the cam. But if I were setting up the build again for a driver I'd probably keep it at a 703 instead. The T56 and gears will solve most of my issues I think, make it easier to take off and still have the overdrive for the freeway.
Here's the 704 at idle, probably around 800 rpm in this video.