So you want a cam for the idle? :nono: J/K.
The E7s are junk, I have "heard" when they are ported they are a little bit better and some guys say they have ran decent times with them, but personally I think they are a waste. I would grab some gt40 heads off an explorer in a junkyard and get them ported, they're better than the E7s stock, but I would get them milled down a little bit to bring the cr up some. I think the combustion chambers are like 70-74cc, I can't remember, I have a book that tells them but I'm doing homework right now. But you should get some stiffer springs for the gt40s because they are pretty soft. I would check around for the prices of porting to see if its worth porting either one of them though. It takes a lot longer to port iron heads than the aluminum heads. You might find that after getting them ported it might be better to wait a while and buy some aftermarket heads. You don't plan on driving it this winter right?