Natalie,
Stick with Peter and ask him for his candid advice, and you'll do just fine if you have ERA build the car for you. Peter can save you a few $ here and there (engine too) by not getting too caught up in the hype of putting a 427 "side oiler" in a street-use car with a "mild" cam, especially one with no rollbar
Those came with 428s (not 427s) originally anyhow if it makes a difference to you. There are some nice "street" version cars with Ford FE 390s and 428s that do just great on the street. At the end of the day, it all looks the same with the same valvecovers and fixtures on top of the motor. IMO: Don't
waste the money. A real nice reliable and worthy iron 427 belongs in an original car or on a nice engine stand if you ask me. I'd recommend using the savings on nice leather seats through ERA, maybe some nice pindrive wheels/hubs, getting the body / street flares done right, including all the right fixtures for the engine and compartment, etc. If you plan to drive on trips or longer routes, you might want to consider a 5spd with overdrive vs. a traditional Top Loader 4speed depending on how "purist" you want the car to be and look. Nobody looks under the car anyhow, so maybe a 5speed. Nice paint and body can be costly. However, it can make a car look like a million bucks if its done right. Like I said, Peter can give you the straight scoop if you tell him you just want a nice car and don't want to go over the top, unless that is your objective. I built my car by the way, and watched others order turnkeys. ERA does a great job. Its worth the wait, and be prepared to wait for a turnkey, it takes a while. Have fun. Good Luck.
PS: There is an ERA Registry poster available now if you want to drool at all the different model ERA cars while you are waiting for yours to be built.