[JRyan]

Ed's right. There are a lot of cars running as a different year then what they actually are. We used to run a 72 and claimed it as a 69 with the 350hp 396. I'm also building a 70 now to run as a 71-72 with the 350 that Al just mentioned. As an automatic it's rated 278 and 274 as a stick which is what I'm currently building. We do all our own engine and bodywork and one of our best friends is an upholestry guy. So the car is fairly nice but, even with that I'll have far more into then I care to think.
So, Alan is pretty much correct about you can't build a super competitive G-H car without spending a boat load. Even if you can do most the work yourself. However, it also depends on what your definition of competitive is. If you're looking to run .6-.7 under and aren't all interested in having it be the nicest car in the country it can be done on a reasonable budget.
I can't say if you're looking to be somewhat budget conscious that I'd look into a 396/402. While the majority of the parts don't cost anymore (pistons,rods,etc). Some of the castings as well as having really good springs, rockers, lifters which require a little more attention. That's the reason I chose to build the new car with a small block. After running our 350HP I knew I couldn't afford to keep up in A-E/S on my own. If you're looking to go -1.-1.25 under you'll have to spend the money for the best stuff no matter what combination you'd choose to use.

Best of luck

Rick Ryan