To make these fittings I put a piece of 7/8" bar stock in the vise and used a drill press and drilled a 3/16" hole through the length of the piece. I then used a 5/8" spade drill bit (for wood) to drill the large hole in the end. Using this bit keeps the hole centered and is just the right size to let you get a socket inide to tighten the nut for assembly(on some of the fittings I used a 1/4" bolt and a backing nut. Then use a 1/4" tap to tap the hole. If you want to you can cut the pieces out of the bar stock with a 1" hole saw. This will give you a concave surface on the part that connects to the other tube. Slide the fitting in the end of the tube and drill the 3/16 hole in the sidesand rivet, then put a bolt through the other tube and tighten. The long bushings are used where the rudder and elevator bellcranks attach, use short bushings everywhere else. If you order these parts form Aircraft Spruce they cost over $16 each. I didn't drill the holes in the side until after the part was inside the tube. I didn't want to try to to align the holes. If you look at the 3rd picture down in the fuselage section you can see the fittings.
Here is the begining of my new motor. It is a bored and stroked 1/2 Volkswagon. I went with an 92mm bore and a 84mm stroke. That gives me a total swept volume of 1117cc. The total volume will be about 1225cc. The stock 4 cyl VW is 1600cc!!! Here is a look at the whole motor. The heads are made from a single 2 cylinder head that I cut into 2 pieces. I then took the end of a stock VW head and welded it onto the end and came up with a nice looking high performance head. the stock valves were 35mm for the intake and 32mm for the exhaust. the new heads have 41mm intakes and 36mm exhaust as well as having larger intake and exhaust ports. The 041 head cost me about $250. Not too bad for 2 heads. I haven't put the guts in yet. I'm still waiting on the connecting rods and the bearing kit. As soon as I have that I can machine up the prop hub and then assemble the motor. The spark plugs aren't in yet so the wires are stuffed into the intake. Here you can see the cylinder covers and the pushrod hole covers. I made all of these things my self. It makes for a neat and inexpensive job.