Been building Air powered rockets for years. Now designing for Estes power.

Have a question about parts that can be substituted without losing any safety.

The biggest part having trouble getting without buying a pack of parts and getting only three of them that are usable.

The Green Engine Block part number F 030164-2? Is there anything easy to get that can replace these?

E engine Hooks will be another issue to get here in Alaska? What else can be used?

Mike