Thanks for the responses......
For those that misunderstood, I am looking to raise compression. After thinking on this a bit, I figure that I may be able to use some simple geometry to figure how much deck needs removed to lower chamber volume by ~3 cc's....
Vol = Pi * R^2*H
3cc = Pi * (4.030/2 * 2.54)^2*H
H = 0.0365 centimeters or 0.014"
This would be the amount milled if the chamber had the same cross-sectional area as the cylinder bore, but just eye-balling it, the chamber looks to cover about 75% of the cylinder bore; so H would need to increase by 1/0.75. This gives about 0.019" required to be milled from the heads to reduce the chamber volume by 3cc. This seems pretty close to what was stated in an earlier post by vetprowanab.
Assuming this is correct, I can see how the P2V clearance will reduce by exactly the same amount milled, but with my cam and piston geometry this isn't a problem.
As for the pushrods, I also see how they will become relatively longer by the same amount, but is 0.020" significant? In looking over some pushrod lengths offered, many of them increase in length by increments larger than 0.020".
Thanks again for the input.
87 Mustang GT - 331, T-70 Turbo, TKO 600