so has anyone here bought a set of E-streets for a big block and used them out of the box with no extra porting? Wondering how much performance was gained over the stock iron heads..
The E street is exactly the same as a RPM head port wise. The “E” (for economy IMO) is due to the different valves, lighter springs and different valve seats.
Who ever has done a iron to RPM head swap could tell you the performance difference.
