Not trying to be a know-it-all but the 7 Litre car engines were not "special". Most show a "Q" for the engine code which is no different than the T-Birds, Mercs, and the rest of the big Fords. If anything, the CJ engines are a "better" block due to the slight casting changes made in '68 and up. Basically, all original factory 428s should not be bored any more than necessary, and usually no more than .030". But being Ford, you never know for sure. If you want a 427 bore, get a 427 block.