Formula to shave pistons to reduce compression ??

I'm sure by the time you read everyone's suggestions mine will have been covered, with that I'm going to say this. Milling is not going to affect valve pockets as they are dependent upon the distance from the pin center to the required spec of the distance from from the valve seat to the pin center at TDC, pockets are machined to give a set clearance with the valve opening in relation to the piston position as it moves in the bore ! You don't measure clearance with the piston at TDC and fully open, as the intake will some what follow the piston as it goes down ATC and ex, is opening as piston is going up to TDC, hence changing valve timing and lift will affect the clearance and usually only requires a small amount of material removed to insure the customary .100 " for exh. and .06 to .08 for intake. Some people like to have the same on either valve and that is probably a good thing when it comes to higher RPM. I lost a set of E valves in a BB once when index pin in the cam broke causing the cam to be SERIOUSLY RETARDED, fortunately the engine stopped running before the damage got any worse then bending the valves losing compression, however the cam failed not long after I patched the problem, I failed to see where there were a couple of tappets climbed a lobe in front of the lobe they belonged on. Anyway, AS others have said find someone that is interested in your pistons and take the lose it would be little difference when compared to the cost of having them fly cut thereby affecting the balance of the set. If you intend to balance the engine before assembly, not such an issue. I'm sure that is your plan. Long ago I built an AMC 401 for a guy from a mix and match up of parts from an earlier 390 and a 401 block. This required using crank rod and piston combination of both and having the pistons cut down .06", they were a dished piston with pockets. By the time I was finished, I had to CC the dishes in the pistons, square the block decks, CC and mill heads, (closed chamber)mock up the engine and CC the complete chamber volumes and do the math. At the starting point of the build, the pistons were above the deck so by the time the engine was ready to finalize, I had .01 deck clearance added to the compressed gskt dimension of .037. A minimum of .04 was my target and I got a little extra just for S's & G's. Point is with dished pistons the only thing at lose was a little metal above the top comp ring but I still had plenty. With flat tops it would have been a lose across the entire piston top but forged pistons are so much better than cast so there would be such little lose in strength. However, using nitrous might be an issue if you have to remove a lot. It is a big issue with the top ring ring land, especially when using power adders. It's good to have at least .200 and any extra is even better. On that note, nitrous loves higher compression as it is a cooling process. Ign. timing has to be reduced regardless, because burn rate is so much faster with all that extra O2 and the freed N2 acts as a shock absorber releasing stored energy back into the effort of pushing the piston down. Someone suggested E85 and that is truly a good idea as it loves compression just like N2O, all you have to do is recal fuel/air ratios. Now comes a truly beautiful suggestion, run away from a carbonator and set yourself up with a really nice EFI system and a flex fuel sensor, all your problems go away without having to worry about 11:1 compression. N2O will still work, remember, adding Alch to fuel will require a richer mixture regardless of how much you add so using a flex fuel sensor with EFI does it automatically. I'm currently working at building a system like this which will have just under 11:1 , not going to mention it's a Chevy though. It doesn't matter what brand it is because it was said a MOPAR SB looks like a Chevy with funny looking rockers, and late model RFI heads have stubs now so they look like SBC's and a bunch of others now. Point is what usually works for one works for the other, most of the time. If you do some research you will find that timing chains for various engines can almost if not fully interchange because they have the same number of links and pitch, the only thing that changes is the specs on the gears, tooth counts and diameters along with fitting to manufactures cams. So back to fly cutting pistons, Don't worry about pockets until you have chosen a camshaft, if you can remove enough metal to get the Comp Height you are wanting and save money even after paying someone to do the machining unless you have a lathe, measure the remaining top land keeping at least .200 along with having the top at the proper spec with the block deck + compressed gskt thickness .04 is a good place to be from any point of the head casting extending into the bore. Do a mock up and all the CCing chambers, pockets, bores can be calculated with math, and calculate volume for head gskt when torqued, some gskts will give a value for you on the listing and package like Felpro does, sometimes. Then considering a variety of cams will ultimately be the deciding factor on compression since the ratio is only a number, valve timing is what matters most since compression is a factor more important than ratio. High ratio engines will have low compression with big cams and until the engine is running in its optimum range ration has less to do than actual compression. You cannot measure actual compression on a running engine, it is always going to read way less. Next is the factor of timing in conjunction with RPM, the faster it is running the less time there is for detenation to be a real issue up to a point of how heavily the engine is loaded, and since forged pistons do so much better under these conditions, a little adjustment to timing can solve most of the problem, which leads me back to EFI, using knock sensors, the engine can be tuned to be at the optimum at all times. Then you have no issues, in a perfect world. You get the best of everything, the more you put in the more you get out applies to the whole picture, more comp, more return, more dollar more return and when you get it all right, it is so cool when you open the hood and can show off all that Super High Tech stuff. I know there are guys running turbos with high comp ratios and EFI and making it all work right so that blows off the old rule of pump gas mostly. It's all in the TUNE ! Raising comp means controlling timing, since higher comp makes more heat, you need to keep the fuel fuel until the right time to make it more heat. So keep the fuel cooler longer makes all the difference. Using methods of getting the air/fuel to its lowest possible point before it goes into the chamber is the key. Fuel needs to be warmed up for vaporization then super cool the mixture on its way to the burn chamber so it has farther to go before it ignites on its own at the wrong time. Keep the chamber as small as possible, going back to the old closed chamber verses open chamber design rules so there is no place for mixture to be compressed by flame front. This very reason is why Hemis are so awesome, no place for fuel to be ignited by compression and killing the power phase with uncontrolled ignition. MOPAR kind of dropped the ball in play with plug location on BB's and SB's were better, the old poly head 318's had a leg up and Toyota 3TC's were pretty neat with HEMI chambers, now hemi and PENT chambers are the norm with twin cams with plugs over center. I love the old engines and I love the new tech control systems, they go hand in hand together. As they say there is replacement for displacement and it doesn't simply mean bigger is better, displacement is all about how much air is being moved and we all know you can as much air in a small package as in a big package when you compress it. So compress it is as much as you can and control it more! That is the way to make real power.