True. Or a much cheaper alternative is the thermostat housing that has a threaded port in it for the sender!
Just a clarification because I’m thinking about doing this on one of my Cougars, I thought with the Holley Sniper EFI unit, you didn’t need a CD box as long as you were using either the matching Holley dizzy (forget if its the hyper spark or the dual sync). I’ve always been a carb guy so figured I’m missing something obvious…? It may be as simple as I’m looking at the Super Sniper, which already has a throttle body ecu mounted. Although, I thought I thought they all did had the self tuning ecu. Edit: I’m also looking at the Holley EFI sniper fuel tank. Sounds like the pumps are internally regulated and I wouldn’t even have to run a return line? My battery is already mounted in the trunk so looks like a simple conversion.
You can use the included coil driver module, but you’ll get better quality spark with the Hyperspark CD box. The distributor you need is the HyperSpark, the Dual Sync is overkill because it also provides cam signal which the Sniper doesn’t use.
Will the Hyperspark distributor and CD module support variable ignition timing with the Sniper? Is the distributor available in a short profile like the original '70 Ford 351 distributor?
Yes you’ll have timing control through the Sniper with the HyperSpark setup. Not sure on the height of the distributors, but they have a model for 351W and 351C:
I was asking because part of the reason I used the Low Profile Holley Dual Sync Distributor (565-111) on my Cougar (https://cccforum.discoursehosting.net/t/holley-sniper-and-msd-ignition-conversion-70-351c-4v/13887/1) was to match the height of the factory distributor and retain the original air cleaner. If a low profile Hyperspark distributor was available I missed it.
https://www.holley.com/products/ignition/distributors/holley_efi_dual_sync/parts/565-111
I have the hyperspark distributor for 351W and it is about 1/2” taller than the modified duraspark it will be replacing very soon. If you need exact measurements I can get them for you.
I guess the simpler way to phrase the question is, will the original air cleaner fit with the Hyperspark distributor?
I have not installed mine yet, but: my original aircleaner sits 1 1/2” above my current Duraspark dist with plug wires installed. I have a 1/4” spacer under my Sniper EFI. That leaves an actual 1 1/4” of clearance. The Hyperspark is 1/2” taller than the Duraspark so in theory there should be 3/4” clearance from hyperspark to original aircleaner.
I can let you know for sure after I get mine installed in the next couple of weeks.
Edit: I am running an Edelbrock Rpm Airgap intake so my throttle body sits higher than a normal intake and I have not taken that into account for the possible fitment issues for you. I will have to measure from the lower flange of the installed distributor at the base of the intake to the top of the current distributor and add 1/2” to give you the exact measurement you will need in order for you to decide if the Hyperspark distributor will fit under your stock aircleaner.
Where and how did you run your wires and relays? I have a 2bbl sniper (550-849) with the hyper spark dist (565-323) ignition box (556-151) coil(555-152) and in tank fuel pump (12-305) on the way for my 2bbl 390.
I’ll get you some pics tomorrow, but:
I made a mounting bracket for the hyperspark c/d box and mounted it under the passenger fender on the rear apron near the top. I ran the sniper power wires and the c/d coil and distributor wires through a small hole behind the passenger hood hinge. I loomed the c/d box power / ground wires and the ecu power / ground wires together from that hole and ran them under the fender apron to a hole at the front by the battery box and connected them with inline fuse holders directly to the battery cable terminals. (Connection doesn’t look the best so I will buy a top and side post combo battery later and attach them to the side posts for a cleaner install)
I made a mounting bracket /plate for the relays and ecu fuse and mounted them to the top edge of the passenger firewall. I ran the blue fuel pump relay wire through the firewall near the fuse block area and down the a pillar and under the drivers step plate all the way into the trunk with the main rear harness. I had to lengthen it a little to attach to the fuel pump plug in harness.
I soldered and heat shrunk every connection that I made. I also loomed every set of wires in TEK braided split loom.
I have not put the fuse in the c/d box connection yet to power it up so I don’t know if I am going to get any RFI or EMI from having those wires so close to each other yet. I shouldn’t, but murphy has a way of sneaking in.
My 12v switched power is from a relay triggered by the current coil + wire. Works great now, but I might have to re-think that one when I change over to the c/d box…not sure yet.
I will be un-pinning and removing several unused wires from the ECU main connector to clean it up some and see if that is causing my very minor RFI signals I think I see in my datalog. (No real performance issue that I’ve noticed yet, but I want to eliminate any possible issues down the road)
Why did you choose Sniper over other EFI? Like FAST or FI tech
I will be un-pinning and removing several unused wires from the ECU main connector to clean it up some and see if that is causing my very minor RFI signals
An un-terminated wire amounts to an antenna. I have unpinned the excess connections and it completely solved the RFI issue on a Sniper install on a Y block Thunderbird.
Well, to be honest, I did not research FAST. I did not like the way FITECH looked and it didn’t perform as well according to someone that I knew who was running that setup. Holley for me was a well known and trusted brand.
I will be doing that in the morning, provided my wife doesn’t throw a wrench into my garage plans. 
I will also run another data log afterwards to confirm it really helped as I firmly believe that it will.
I have rocket mans predapter 001 and I was thinking of using that keyed 12v source to operate the sniper and hyper spark.
That should work.
Here are the pics I promised: (yes, I still have some prettying up to do on some wires)
Good work, I like the idea of hiding the CDI box. Any concern with debris or road spray from the tire?
No, the box is fully sealed. I originally built the bracket as an enclosure box, but had no way to put the screws in to attach the box to it. So I cut off the enclosure part and left it as a mounting plate.
Mmm, not sure I’m going to mount the cdi box in the wheel well. The gravel road will not be kind…I do like the firewall mount.