P to v clearance is minimal during overlap -- when the intake is just opening, and the exhaust is just closing, and the piston is passing through tdc at the end of the exhaust stroke and the beginning of the intake stroke. Consequently, the valves are only open around .07-.08" at that point in time. Do the math - a change in rocker ratio only reduces p to v by about 5 THOUSANDTHS of an inch. Nothing to worry about unless you're right on the ragged edge anyway. And if everything else is stock, you're not on the ragged edge of clearance.
The switch from 1.6's to 1.7's on a stock 86 won't cause any clearance problems. Now, if you're running an aftermarket cam, and have reduced p to v because of that - then you need to do the math. What was you clearance with the 1.6's (you did measure, right?)? Subtract .005" from it, and you'll have a pretty safe approximation of what your clearance will be with the 1.7's.