I've been away from these forums for a few years and it's good to be back. I'm glad to see some of the old names are still here.

Now on to business. I have an OS AX .55 that never ran well for me regardless of prop sizes.

By chance I found out that my SF .46-P pump carb fits the .55. This carb has a HUGE 9mm venturi. So, I tapped the back plate for a pressure nipple and hooked up the pump. I bolted on a tuned pipe header, too.

Soon, I will bench run this AX .55 with the SF .46 pump, pump carb and a tuned pipe. Let's hit 16K!