question about align bore/hone & main caps


New Member
Sep 10, 2003
I bought 2 brand new steel main caps and had them fitted on a block with the stock front and rear caps. They align bored/honed these caps with ARP studs. Well it ends up that the block has to go to .030 and I have .020 pistons. So instead of buying new pistons I want to bore my std block to .020 and use that block instead of the block I just had the aline bore done on.

So, can I use the steel main caps that were just aline bored on the std block and have them aline HONE this block? Reason I ask is that I dont want to spend another 250 on an aline BORE if they were just done. Shouldnt the bore be the same size on these new caps as they are on the front and rear stockers from the other block? Wouldnt an aline HONE clean them up enough to use?

Machinists/builders please respond.
Sure they're the same size. But they've been cut to match one block, and you're moving them to another. Any bets they wont line up?? Not my money.

I've got two seemingly identical blocks here, all with billet mains. Can't swap caps between them though. Tried a dry fit, and they mis match by over .125" :eek:

You may get lucky, but then again, probably not.
For my money, I'd move forward with the block that's already been align-bored, and set up for the new caps.

The main saddle is what's used to locate the block for the bore/hone operations. Since that process has been completed, you're ready for a highly accurate location of the newly finished bores, if you use the block whose main saddle is dead on.

Typically, an align-honing operation isn't drastically cheaper than align-boring...and an align-bore most likely WILL be necessary. (I'll let other people chime in on the reasons why.)

Most likely, you'll find a buyer for the +.020 pistons without much trouble. You didn't mention the piston brand, but I'm guessing they're JEs, or equivalent. The loss you'll take on them will be offset by the amount you'll save in not having the second block's main saddle machined.

...and, you'll save yourself from having even more meat cut from the new steel caps...
We just did this, removed steel caps from a customer's damaged 109 block and fit the to another. All the work has to be done over. You might get lucky and only need to hone, but we mill the block to fit them each time.
Quickwrench said:
Most likely, you'll find a buyer for the +.020 pistons without much trouble.
What would you take for the JE's pistons?
Told you... ;)

If WINDMILL doesn't take the slugs, let me know. I have some items to trade, if you're interested.