For headers, 1 7/8" TTI's were listed for the RPM heads I run in an E and fit as advertised. I told TTI I would be running Ed heads and I believe they put some small reliefs in to help with the angle plugs.

For intake, as Andy says, EFI helps. I fit a M1 single plane under a flat E hood with short EFI throttle body and mild drop base air cleaner.