My Holley Sniper install thread

[Firetodd]

I will be installing the Holley Sniper efi master kit over the next week or so. I have one question before I get started. The coolant temperature sensor that came with the kit is 3/8" npt. Where have others installed it? My 383 has a plug near the heater hoses and water neck, but I wonder if that's my only option besides buying a spacer under the water neck with a 3/8" port.

Besides that question, everything else seems to be a simple install. I will take pictures as I go along.

[JR]

This thread will probably get moved, but it will be interesting to watch. I'd like to see how the sniper works out.

As for that coolant fitting, I took the easy way out and used the spacer between the water neck and thermostat housing on the water pump.  But I've been told that replacement aluminum water pump housings have the necessary npt hole already threaded in them.

[Arkgl01]

I have a shop doing it on mine too! Hope its easy to install.

[Firetodd]

This plug was actually fairly easy to loosen. I was able to use a large socket wrench and to my astonishment it broke loose and could be easily removed. It appears that I will need a bushing as the coolant sensor is a hair smaller in diameter. Anyone know the size off hand?

[Charger_Fan]

Anyone know the size off hand?

Looks like 1/2" NPT to me.

[lukedukem]

Very exciting thread for sure. i will be watching as well....
good luck

Luke

[igozumn]

I bought an aluminum water pump housing (mancini) that had 2 temp sensor ports.  My buddy had a Fitech installed on his '69 Nova and they/he used a thermostat housing spacer.  Has 2 ports in it.

[John_Kunkel]

This plug was actually fairly easy to loosen. I was able to use a large socket wrench and to my astonishment it broke loose and could be easily removed.

You gotta be a lucky guy; I have fought those plugs to the point of having to drill them out.

The temp sensor is typically 3/8" NPT so you need a 1/2" NPT to 3/8" NPT reducer bushing. A face bushing is best for this because it allows the temp sensor bulb to sit deeper into the coolant.

https://www.ebay.com/i/172698036357?chn=ps&dispItem=1

[Firetodd]

I used an electric impact drill and the plug didn't budge. I wonder though if the shaking helped it though - because the long socket wrench moved it easily after that

I saw those face bushings but just picked up a regular one. The sensor did screw almost all way down though. If there are any issues I will swap it out. Anyway, here is the sensor in place with the 1/2" NPT to 3/8" NPT reducer bushing:



I will be doing a Father's Day car show with my father in law and his Impala, so I gotta get this done by Friday night. Tomorrow, I will mount the throttle body, mount the -6 an bulkhead adaptor on a new fuel sending unit for a return line,  and mount the electric fuel pump and filters. Then hopefully I can finish and tune on Friday. Wish me luck!

[lukedukem]

What about the fuel tank. What did you use there.

Luke

[Firetodd]

I have a stock fuel tank. I purchased a new fuel sending unit. I will install the return line fitting into that. Since I have a first gen charger they don't make a FI ready tank, and I didn't want to remove, clean, and then install the bung into the tank. Holley suggests installing the return line adapter into the sending unit or in the filler neck.

[Firetodd]

In trying to figure out where to mount the electric fuel pump and filters, I've run into a problem. Holley states that I should mount the pump below the lowest point of the tank, which makes sense since the pump pushes fuel and needs a gravity feed. I'm not sure that I have any great locations as my tank appears to be pretty much the lowest. See picture:



Good news is that I won't have a problem mounting the new sending unit:

[Firetodd]

Any fist gen owners have any ideas?

[JB400]

Since you're using the stock tank and sending unit, I'd mount the pump either below the sending unit or at least level to it.  I wouldn't mount the pump below the fuel tank unless you were going to cut and mount a sump in the bottom of the tank.

[Firetodd]

With the Fathers Day car show on Sunday I had pretty much resigned to wait on the install. And then yesterday morning I got called in for overtime at my fire station 8 next to my fire department's maintenance facility. I got to shift at 7 am and drove my Charger 😏

After getting our daily chores done I briefed my crew on my plan of installation. We started with mounting the fuel pump and filters behind the front passenger wheel on the frame rail. I figured that if we got calls I could drive to the car show without doing anything else:



I picked that location as it was th only spot big enough lower than the tank.

[Firetodd]

Then I decided that since I was using my old fuel line as the return, I would route my new fuel line and zip tie the new line to the old one:

[Firetodd]

Then there was a decision point to see, "do I now swap out the sending unit and try to finish the install or stop and drive my car to the car show with the carburetor?"  My crew said let's go for it and I agreed!

[Firetodd]

 We siphoned the gas from my fuel tank and made all kinds of jokes about if we were going to catch ourselves on fire and be on the news for a firefighting crew that burned up trying to siphon fuel from an old car.  Once we got the fuel siphon we pulled the filler neck off and drop the tank and swapped out sending units. We had decided previously since we were using the old fill line as the return line that we would put the return line bung in the filler neck. Here is the mount of the bung.

[Firetodd]

Next we hooked the old fuel line to the return bung and then moved to front and removed the mechanical fuel pump and terminated the old fuel line with the new fittings and connected the return line. We installed the oxygen sensor, and dropped the car.

[Firetodd]

Then I pulled the carb and took a picture of the linkage:


I dropped the new throttle body on and routed wires, terminated ends, and hooked up the return line and pcv hose. I connected the O2 sensor and coolant temp sensor. Then I remembered that I forgot to hook up the electric fuel pump 🙁. So we raised the car again and hooked it up. We dropped it again and then hooked up the 12 V switched and battery wires. At this point we had been working for about 6 hours. I wanted to start it up but then realized I had never hooked up the throttle and kickdown linkage. The Holley doesn't hook up anything like the edelbrock carb it was replacing. At this point it was 11pm. I still had one firefighter helping me. And he was only still there to see it start

We were able to rig the throttle cable. I plugged in the handheld and turned the key on and went trough start up wizard. When done the fuel pump kicked on and we ran some fuel through new line into a fuel can. I then turned the key off and terminated the fuel line and hooked it up.

I turned the key on and waited 3 seconds and started it. It fired up immediately and sounded like a funny car at the drag strip! The motor raced and the RPMs were at 3100 and climbing! I shut it off and redid the wizard and checked everything over. I then tried again and it again raced at 3000. Ugggh!

[Firetodd]

At this point, I told the other firefighter to head in and I would clean up and shut down the shop. I finished and pushed my car out of the bay unsure of how I'd get home in the morning and knowing I'd miss the car show. I showered and hit the pillow at 1am. I woke up at 5 am and thought since I got off shift at 7 am I could possibly rally for the win and drive it home. I figured it was racing because I either had a vacuum leak or the linkage was off.

I tightened the throttle body down again and then disconnected all the linkage. I then turned the key on and fired it up. The car idled at 900 RPM! I then had to figure out how to rig the linkage to make it home. I did but had to disconnect kickdown linkage because it was keeping the "secondaries" cracked open!

[Firetodd]

I headed home and decided I would have to hit the auto parts store and get some Holley adaptor for the linkage. And then I ran out of gas. Dang it. I guess if you siphoned out your fuel tank that can occur! I called a friend and got some fuel and drove  it home. I can't wait to get the linkage sorted out to truly drive the car and have it learn. Anyway, if you can borrow the use of some lifts and have some extra hands, this install is not that bad. I'm a novice and it wasn't that bad.

Btw the Holley website says it gives you 40 feet of fuel line but there was only 20. And you may need hose hangers and 4 more hose clamps than the kit provides.

[Firetodd]

I called tech support and they told me to order a 20-7 throttle adaptor. So I should get that next week and can truly drive the car and let it tune itself. I did do some driving today and it started and ran flawlessly. So far, I am very impressed. Tomorrow I will make it to the car show. Life is good.

[JR]

Congrats man, that is a clean install!

I would bet you'll never go back to a carb. EFI is fantastic.

[Kern Dog]

I called tech support and they told me to order a 20-7 throttle adaptor. So I should get that next week and can truly drive the car and let it tune itself. I did do some driving today and it started and ran flawlessly. So far, I am very impressed. Tomorrow I will make it to the car show. Life is good.

That adapter is available through Summit overnight. It is the same one used on the Holley type carburetors for this same reason.