Assembled height formula, what am I missing?

[Midnight_Rider]

Ok, I've been looking at the stroker kits on the 440 source website... and something's (literally) not adding up for me. I'm sure it's something simple that someone more experienced would know or catch right away.

As I understand it, the formula for assembled height is: (stroke ÷ 2) + rod length + piston compression/pin height.

Let's look at the 440 >> 512 kit:

2.125 (4.25 crank)
7.1     rod
1.485 piston (-27cc variety)
---------------
10.710


Deck height on a 440 is 10.725?

But yet on the charts on the 440 Source website, it's showing that combo as 0.010" below deck? Where did the other 0.005" go?
http://store.440source.com/Stroker-Kits/products/3/

[cdr]

a

[justcruisin]

I wouldn't get concerned about it, BB mopar deck heights are all over the place, not uncommon to be .010" out side to side or end to end, your are going to want to have the deck cut, just check you have enough height for the kit (may have been decked before), mock it up and have it cut to suit.

[John_Kunkel]

  By the time you get the block squared there might be no deck height or positive deck height.

[BSB67]

27cc is a really big dish.

Anyways, target the head to piston clearance (quench) that you want, decide the gasket you want, and then cut the deck to get the number.

[Midnight_Rider]

Thanks guys.

I'm guessing 440 Source used a 10.720 deck height for their figures? I was seeing 10.725 on the net. Just wanted to make sure I wasn't out in left field with my math.

27cc is a really big dish.

It looked like a big number to me too. But with a 4.25 crank, a 78cc head (Trick Flows) and 0.040/0.045 quench distance, it's putting compression in the 9.9/10:1 range... at least with the Wallace calculator. The next smallest cc dish piston in the 4.25 crank Source kits is -17, which puts it at 10.75:1. An 82-83 cc chamber would get it down closer to the 10.25 area I am shooting for. Or a -22/23 cc piston.