What do I use to messure the valves in a head

Well, it all depends on the condition of the heads, how many valve jobs they've had and what you've done to the engine and drivetrain.

* Even with a new quality valve job, if a head has had several and the valves are sunk, it will flow less air.

* You can take a worn out 1.88" valve head and regrind it for a 2.02" valve and it will flow better because the seat is nice and high in the chamber.

* A 2.02" valve will work better at higher rpms, say 6,000+. But a 1.88" has the potential of running faster because it can provide more torque through the low end and mid-range, where your car spends most of the time in. (Area under the curve.)

* If you do get new valves for either head, use stainless nail-head style valves. They flow better on the intake side. Exhaust usually like more of the OEM tulip style, but it isn't a big difference.

So lots of little things to look out for.