1st: I paid $14.00 Cdn at a local auto-wrecker, many (?) years back. 2nd: NO regrets.
Like most who have done the "GM Coil Conversion" mine was similarly located in the "Tool-Tray" but I found it a nuisance when changing the air-filter and other routine "stuff".
Looking for an alternative location I discovered it fit above my cam cover, mounted to the underside of the plate originally used to hold the OEM coils. Before anyone considers this there is one required modification which I had unwittingly and coincidentally done way back in '83 when the bike was stripped and gutted for plating and paint. At that time I "Decked" the cam-cover solely for cosmetic reasons. By this I am referring to removing the reed-boxes integrally cast on top of the cam cover. (I filled the air-ports in the cover with high temp. epoxy which is still intact to this day and has never needed any further attention.) With the cam-cover slimmed-down the coil-pac fits perfectly! And it coincidentally (decades later) allowed me the room to make a custom air intake/air-filter modification which also gave back the space to return the tool-kit (less the tray) to the original location above the battery.
The advantages are: 1) A cheap, easy and viable coil replacement option, 2) A much healthier spark, 3) A more suitable/cosmetically appealing location, 4) MUCH shorter length spark-plug leads ( as they were with OEM coils) as well as Ballast-Resistor supplied power and ground leads., just to mention the most obvious. From a maintenance point of view I find it's easier to remove the GM coil-pac as opposed to the OEM coils when servicing requires the removal of the cam cover. Pop the plug-boots, remove four fasteners and the coil-pac can be removed out of the way with no further disconnects required assuming you wire-up with several extra inches of power/ground leads.
What I found humorous about "this Guys" Ebay ad for these coils is it appeared after I had posted my GM conversion on this forum. He made the mistake of using my photos for his Ebay ad. It was his disclaimer: <
I have not installed any but have sold over 50 right here on eBay> that galled me. At least he read our threads and included the required comment about the "Ballast-Resistor" !
There are many coil conversion topics and threads and I'm certainly not discounting their viability and effectiveness. For myself, The GM coil-pac conversion was worth the try and immediately proved itself to meet the engines requirements in an affordable and simple way which was worth the effort and no more involved then any conversion. It works for me beautifully and I would recommend those needing replacement coils, consider this option. I will add: "Engine Heat" degradation of the the GM coil-pac as I have seen commented on (only a few times) is in my opinion a moot point. Have you seen where they're mounted in/on a vehicle? - usually on top of the intake manifold and hidden under a "cosmetic" plastic cover !
_