Dont let possible spark plug interference be the deciding factor on head choice..
Buy a head that you later can grow into or send out for some major porting to pickup some real E/T.
Go with the Indy's. Later on when you want to go fast..which we all do at some point. You can send them out, have them ported add the matching cam and pickup a half second in E/T.
This is exactly what I did.
Accel makes a shorty plug also.