How often do you change headgaskets if everything's ok?

I seem to recall seeing that some of the YS big dogs changed their headgaskets after 20 passes or so.

My car still runs well and has good compression, but I've noticed a trend in my compression numbers... they go down every time I test the motor.

I tend to test it every 6 months or so... 6 months ago they were between 155-165 psi. This time they were between 135-142 psi.

Is this a sign of the head gasket seal slowly going south?

Thanks!

FWIW I use Felpro 9333 PT-1 head gaskets... my cylinder heads are oringed.

Andrew,
I try to change mine every 20-25 runs(9333, o ringed head), this seems to be what most of the headsup class racers that run these gaskets do. I have about 30 on this set, its TIME.....hehe. last pass I saw 29psi with the X trim, all is well.......you will find that they fatigue, they dont really melt unless you have a mechanical problem, just fatigue and will give out. JMO.

Interesting. It looks like I'm about 70 passes overdue in changing mine... I wonder how much I would pick up if I did?

well in columbus 2 years ago, the best the car ran was like 10.1 and a 10.20, on the next pass it blew the gasket(no change in tuneup), I changed the gaskets and changed nothing and it ran a pair of 9.90s. could have been a number of things, but it did go faster.....hehe.

Thanks for the info, Spence!