This is for a factory four-bolt LT1 block.

The machine shop is zero decking the block. However, their charge for aligning boring/honing for fitting aftermarket billet caps is kind of pricey.

If I understand correctly, deck height is measured with the rotating assembly mock assembled.

So, if I have the machinest zero deck the block without align boring/honing, then take it to another shop to align bore/hone, since the crank centerline will move, will the rotating assembly "move up" closer to the deck? Enough to have an adverse effect on clearances?

Thanks.

 

Sure align boring/honing moves the crank centerline up toward the deck. If it was just an align hone with original main caps this might be only a few .001's. With new caps, it kinda depends on the machinist.

I would have one shop do all the block work. Install the caps first which will mean align bore/hone. Then locate off the new main bearing bores to deck the block. Otherwise, the decks might not be parallel to the crank centerline. With two shops doing the work, who made the mistakes if things aren't going well? You'll be in a big urinating contest.

 

Usually the align boring/honing process involves just taking a few thou off the FLAT part of the main caps so they sit lower into the block. Then they bore/hone out the mains again. Basically, the part of the main saddle that is in the block doesn't get changed very much- it's mostly coming off the main caps. The difference in deck height should be almost nil. Ditto, the need for a different lenght timing chain.

However, I agree with the importance of having a SINGLE shop do all the work. Going here and there getting different operations done is not usually a good thing in the long run. Nobody will take responsibility if something doesn't "line up" in the final assembly, let alone if the motor blows up shortly after install.