In article that praises George Curme's 100 year old “Origin and Force of the Split Infinitive” (Modern Language Notes 29 (2), 41–45), Geoffrey K. Pullum draws this gem from Curme:

Curme makes one observation that I had thought much more recent: that in some cases infinitives must be split (unless you simply abandon the attempt to use the adjunct). He cites an example containing the phrase sufficient to more than offset the losses. It cannot be recast as *sufficient more than to offset the losses or *sufficient to offset the losses more than: These are ungrammatical.

(from htttp://chronicle.com/blogs/linguafranca/2014/12/11/george-curme-21st-century-grammarian/)

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