You got me, I should of added to re-hone it after filling I guess I didn't want to type much when I posted that and assumed the OP would hone the block for new rings. As for distorting the block, if anything the fill would push inward making the bore smaller no more than .001" and probably a fraction of that. I do believe that the original post said that he wanted to install new rings and the machine shop he took the block to should of advised him to hone after filling. Derek
It does squeeze the bore about .0008-.001". I wouldn't worry too much about the rest of the block getting jacked around on a Nail or any other Y-block. Certainly it's not preferred to fill first, but I've done a bunch without drama that I wasn't doing more than cylinder work. The water jackets are up away from the bottom of the cyl's on the 425 already, I doubt it would affect much for oil temps. You can nearly fill the block for about $50. A different block would be less than sleeving this one. If there's never going to be a ton of $$ put into this project I would just run it. If I was given a +.060" 425 block and it didn't sonic great I would fill it and only use it for a short lived, high powered project. I rarely work with resto's or stock grocery getter's though.
