the machine shop can work out the deck just tell them what you want for deck O? or 005 in the hole or 010??you just need the piston your using and you can work out the piston CH or look the piston up lets say if a speed pro it will be listed in speed pro piston book and many others list there ch of there pistons if you have there book or just work the Ch out be finding the piston center line of pin to top of the deck of piston thats the Ch. all makers of piston will not have the same ch .when you have this you add it to the length of your rod stock is 5.700 and then if stock 350 crank 3.480 then 1/2 of that 1.740 then the piston CH lets say is 1.550 add all up crank 1.740 .rod5.700 piston 1.550 your at 8.990 deck for O deck then if you want the piston to be in the hole add what you want 005=8.995 or 010=9.000 deck .to work out the CR of the engine you need to know the size of the cc of head chamber .head gasket fire ring and how thick the gasket is or cc.then were is the piston is in the block O deck ? or what . then the cc of the valve cuts in the piston . the bore size then stroke. then run the numbers there is many on line calculators. many pistons books will get you close .but i allways run the numbers and cc the heads and pistons so i know it what i want if not i mill heads or use a head gasket with less cc or both