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Old 11-07-2017, 01:54 AM   #1
Ryan Hubbard
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Join Date: Aug 2007
Location: Mission Viejo, CA
Posts: 220
Holley Terminator EFI Install

I installed the Holley Terminator TBI EFI system in my 71 C20 pickup a couple weeks ago. I also have it controlling my 4L80E transmission. Here is the spec for my truck:

350 4 bolt main bored .030 over
Edelbrock Performer RPM Heads
8.5:1 CR
Manguson Eaton Rotor Supercharger (12 PSI Pulleys)


Rear Axle:
Dana 60 with 3.55 gears and Detroit Locker

The install went pretty well, I had a TCI transmission controller installed in the truck so I just reused the hole in the fire wall for the Terminator wiring and mounted the computer on the glove box door. ( I have a billet aluminum glove box door) I also used the Holley Fuel pump kit with the filters, fuel line and fittings.

I also installed a small cap HEI electronic distributor so that the Terminator system could control the timing for the engine. I am still using my MSD 6AL ignition box too.

Since I am running a roots blower, I had to change out the MAP sensor to one that referenced the manifold vacuum/pressure after the blower. I just cut the plug of the wiring harness and connected a new plug and some longer wires and told the ecu that I had a 3 bar Map sensor.

Once I got the system installed, I followed the instructions and was able to set the initial timing and got the engine started and running. Once I got the engine running it took a little "tweeking" to get everything dialed in.

After the initial starts and tweeking, I started driving the truck and noticed a big improvement in drivability. I have now put over 1000 miles on the truck with this system on it and towed my other 71 K20 pickup over 600 miles and was able to get 9 mpg towing while still maintaining 75-80 mph on the interstate. (Before anyone says anything, my truck has 4 wheel disk brakes and trailer brakes and I was following the posted speed limits). I had done a lot of work on the carb for this truck and it was a well tuned carb but still not as nice as this system. I am driving another 700 miles tomorrow without the trailer or truck and I will see how that drive goes. But I was getting around 13.5 mpg with out the trailer. I am going to tweek the tune a little on the trip tomorrow and see if I can get a little better mpg. Not bad for a truck that has 550 Hp and over 500 LbFt of torque.
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Old 11-08-2017, 08:26 PM   #2
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Re: Holley Terminator EFI Install

I want to Try one of these Kits on my Jeep CJ5 304 v8
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Old 11-10-2017, 11:02 PM   #3
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Re: Holley Terminator EFI Install

so I was wondering, the cost of this unit worth it ? if cost was a factor....
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Old 11-11-2017, 12:48 PM   #4
B. W.
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Location: Bigfork, Montana
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Re: Holley Terminator EFI Install

Hey, would you mind posting some pics? I am thinking about a similar setup.
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Old 11-18-2017, 01:44 AM   #5
Ryan Hubbard
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Join Date: Aug 2007
Location: Mission Viejo, CA
Posts: 220
Re: Holley Terminator EFI Install

Originally Posted by YoungPup1977 View Post
so I was wondering, the cost of this unit worth it ? if cost was a factor....
The cost of this unit was a small factor but I was leaning towards the FI Tech system but they did not have a way to have a TPS output to a transmission controller. I was replacing my transmission controller because I was tired of dealing with the TCI controller. Once you look at the cost of a good controller and the fuel injection system, I decided it would be nice to control everything from one connection to a laptop.

I now have over 3,000 miles on this system and I couldn't be happier with the performance. I have tuned out all the "issues" which were just small tip in issues with the unit going lean. I am now tuning for economy.
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Old 02-04-2018, 02:31 AM   #6
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Location: austin, tx
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Re: Holley Terminator EFI Install

I just received my terminator kit. Nice to see you have had good luck. I had a fitech and PCS simple shift. I had to use the carb tps sensor and heard people using a y split to tap into it, but since everything was pulled, I wanted to clean up the wiring and have one system. Almost went with the msd atomic, but still a couple of boxes. Looking forward to hooking them up to my Dakota digital gauges to since they talk to each other.

My 4l80e has a shift kit in it and always shifted really hard from 1-2 with the old controller. You notice any difference between the tci and the Holley as far as the trans controller goes?
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