[Jim B]

In the past, NHRA has used 90% isopropyl alcohol and food dye in a pyrex graduated burette. You would have to check with a current teardown participant to verify they haven't changed that. The reading should be taken at the bottom of the meniscus. I've seen some pretty desperate measures in the barn trying to pass a close combustion chamber. Wire brushing, ice (more than one or two times) , asking to use the racers own burette or plexiglass plate (yeah right!!) leaking valves, and some other attempts that were an insult to the teardown crew's intelligence. Volumes are always best checked and corrected before a trip to the barn. I've seen a spark plug change make a legal head check illegal. A ½ to one cc's worth of cushion at room temperature will save disappointment and embarrassment. Port runner volume is a whole other conundrum but forethought and checking can prevent a surprise.