I have established a fine relationship with F26 emulsion tubes in my hot rod 2.3 liter with S-cams where F3s are the rule. I think the relationship with E-tubes is rather like that with people in that you find what works & build on that. There is perfection of the mind but acceptance works pretty well also. As long as the key requirements are satisfied there can be some flexibility in the middle.
Rebuttals?