270s are close with the stock valve reliefs, very close. He is going to properly degree them right? He had damn sure better degree them and not try to use the factory marks.
As far as a tune, it will run like **** until its tuned, I would not run it around untuned. You can do just fine with a mail order tune, sometimes as good or better than a dyno tune because a good remote tuner will use your datalogs from the street. When I say good remote tuner, I don't mean bama or steeda btw, I mean someone who actually datalogs like MPT.
2000 Mustang GT Steeda #0048
Just because I give you advice, doesn't mean I know more than you. Its just means I've done more stupid ****.