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I have had great results from my steel bungee, But I too have a "bought" aircraft. Built before the plans change that installs the doubler shown in Stans photo.
The area behind has cracked "imagine a line from front to rear passing thru the center of the hole". I have repaired and installed a similar doubler as shown above.
just a note to older airframes built to plans not using doubler (users must have had cracks before steel bungee design hence the reinforcement to area)
The doubler is part number 6B8-10 "Forward Gusset" on drawing 6-XB-13 of the CH601XL illustrated parts catalog.
I need to clarify a couple of things on my above post. The Viking Bungee instructions call for a 21/64”, or 9 mm drill bit for the final hole size. I had a 12” long 3/8” bit, so that will work fine too. The 12” long 1/8” drill bit I mentioned is for drilling the pilot hole. Also, if it is not obvious by looking at the photos, the reason for all of this is the engine mount tubes are directly above the 2 required holes and the extra length drill bits allow you to still drill out the holes by coming in at a slight angle.
A good alternative (actually, a great alternative since it's an excuse to buy yet another tool! Haha!) is to use a Dotco 90 degree drill:
You can get very short threaded drill bits that, coupled with the 90 degree drill, allow you to get into very tight areas. There were several areas on my plane where a 90 degree drill was the only way you could get a true 90 degree alignment of the drill bit relative to the hole.
These are very heavy-duty, commercial quality drills ... also very expensive if purchased new! However, they are always available used on Ebay for usually less than $100. I also bought on Ebay several dozen resharpened threaded drill bits in a variety of sizes and lengths that were very inexpensive - and very sharp! Worked great!