Cobra 1,

I have built both the GP Pitts & Christen Eagle for two customers and thought that the firewalls and cowls were pretty much the same. The Pitts got the OS 300 and the Christen Eagle a Fugii 50.

If you look closely at the photos I posted ealier on this thread, you will notice that I added three 1/4" plates to the front of the original firewall of the Pitts in order to get the recommended 6 1/2" spacing from the firewall to the engine thrust washer using the OS 300. This measurement is the same on the Pitts & Christen Eagle. Are you sure that the OS 300 was mounted without any spacing? Can you post photos?

Thanks,
Jake