I want to have my 454 zero decked to build my 496 with. Going by JE specs their pistons and compression ratios are figured at 9.8" with .020 in the hole. Would this make a 9.78" deck height zero deck?? My machinist wants to mock up the two front and rear pistons, measure and deck from there. This sounds good and I understand the concept, but the shop that is balancing the assembly might not necessarily match those pistons and rods together afterwards. This could lead to a slight variation in true zero deck. Is doing the mockup just as good as cutting the deck square at 9.78" considering the assembly would still need to be balanced and possibly not the same pistons and rods used front and rear. Am I making sense on explaining this??
Caleb

you make them all weigh the same,mocking up the assembly is the way to go unless you have the proper equipment to check your dimensions with the stuff laying on a surface plate.

My machinist square decks by measuring up from the crankshaft centerline to the front and rear piston bores deck surface . If the crank is correctly indexed I cant see how you would have a problem. If the rods are all resized then the piston/rod assemblys will all be exactly the same length!
Maybe BillK can comment on this.

Just to add a little more info, my rods are scat H beam 6.385", my crank is a callies dragonslayer 4.25" and the pistons will be SRP with a 1.270ch. IF every component is right on the money and going by SRP's piston guidelines I come up with 9.780" being 0 deck. If everything is off but within specs, there is still a chance that the mockup might be with the tallest piston and longest rod and when the assembly is balanced these might not be chosen to be together(by the balancing shop). Since there is a chance for a very small variation I would just rather cut to 9.780" and not worry about the mock-up since they can still possibly not be matched up the same as the balancer will put them. I will still probably have it mocked up to cut to 0 deck height just to see how far off or how big a difference it comes out from what I calculated.
Just really wanting to know if it is completely necessary to mock up and measure if using new quality parts that should be right on the money size wise.
Caleb

Caleb,
There are too many variables involved to chance it. It only takes about 45 mins to mock it up and do it correctly. If there is a .002 tolerance range for each part, and each one is off .002 to one side, you could have a .006 error !

Caleb,
Another point. When the parts are balanced they are match weighted.
All the pistons will way the same & all the rods will weigh the same so you can interchange them without worry as far as weight goes & it will not effect balance.
The only problem would be if the pistons were not excatly the same size & were bore specific which with SRP's is highly doubtful. They are an excellent piston & I can't remember the last time I had a set that varied more than a couple of tenths.

Thanks for all the replies...it really shed some light on what takes place when balancing. I was under the impression that lightest piston would go with heaviest rod, not that all would be equalized and could be interchanged. I am going to go ahead and mock up to get zero height correct.
Thanks again
Caleb