My ross pistons for my stroker are .017 in the hole, so i'm going to have the deck milled and the machinist is talking about mocking the pistons up to check how square they are, which is a bit of a pain as it means extra journeys and it got me thinking what amount it could be out. Years ago, i checked one of my old engines with TRW six pack pistons and it was about .003 from lowest to highest.
Mick

.003 is a fair amount to a real machinist, and I rather like that...but the decks also get distorted from fastener tension.
Do it right, and you never have to think about how good it is.

At .003 you could deck it .014, get good quench and no piston would be above deck.
Mick

You would want to check all four corners of the block.
My 360 block was 0.010" off front to back and twisted side to side where one side the front was 0.010" higher than the back, and the other side the front was 0.010" lower than the back.

I've seen .008 differences in rods center to center lentgh on 426 Max Wedge and stock 440 LY rods, .003 on after market steel H beam forged rods I used a set of Oliver billet steel rods on one blown 426 street Hemi build and it had similar differences in deck hieghts, you really need to check the stroke also to help determine exactly where the problem is coming from

Decks can also be tilted, not perpendicular to each other and to the bores.

R.

On my 400 block, the pass side was .002 difference end to end.Rear of dr. side was s the same as the pass. side but the front of the deck was .020 taller.(!!!) Cut it and know where it is.

Sounds like the GM "W" 348 and 409 engines with a 74-degree deck angle.

The first time I ran into different length rods was when I was assemblyimg a NHRA legal Stocker 425 HP M.W. motor, I had used the #1 rod and piston to check all four corners and then had the block cut to get the NHRA legal spec. deck hieght. I assembled the motor and decided to check the deck hieght on all eight pistons luckily, I saw from -.017 to -.028, .023 was the spec. deck hieght I was shootong for so I ended up calling the machine shop that I had taken all the 1963 M.W. rods I had (43 of them)and the eight pistons to build that short block to find out what had went wrong. It was the rod center to center lengths. I had assumed he would get the center to center lengths perfect It ended up he had no way of doing that
Never assume
I've ran into block that tapered from the front to back on one side one way and the exact opposite on the other side I've also seen them tapered from the cam side to the motor mount side, a real beech to get the intake sealed up properly If a man is involved making it, he will screw some of them up

After reading this, i will take it back after mock up, thanks for the replies.
Mick

Wow, there's no way to accurately measure the rods and machine them to be all the same exact length?

It can be done but it requires some special fixturing which not all shops have. Shops that do rebuild work don't care about matching rod length since if it came from the factory then it is good enough to go back in a rebuild.

Most good Hi Po shops can do that now Ask them first though I've seen .003 differences in length on a good brand afterarket steel race rods