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Username Post: Holley HP TBI with LPG/Autogas Upgrade        (Topic#350723)
Posts: 54

Age: 60
Loc: South Africa
Reg: 06-26-12
04-21-18 02:01 PM - Post#2731764    

Hello there folks,

I haven't posted in a while, mainly due to cruising all day long with this awesome Holley HP EFI System that hasn't missed a beat since I finally got it all working properly!

I have recently been playing with the idea of installing a LPG system in my truck for highway cruise in an attempt to save a few dollars when traveling for days on the road. Few infos with respect to my setup:

- 1979 Chevy C20, 454 V8, Turbo400 Transmission
- Holley HP EFI4 BBL TBI
- HEI Distributor AUTOLINE D2105N
- Mallory Promaster E-Series Ignition Coils 30440

The only time I would like to use LPG is when hitting the highway - I'd basically run primarily in the highest gear at one RPM. I'd switch back to petrol as soon as exiting the high way.

As such, I'd only need the cheapest type of LPG system - a simple Single-Point-Injection, Lambda-Controlled Carburetor/Venturi system. These are not super expensive, here few options: r-c...

There are basically two of such super-simple systems, these are the KME Bingo-M: nt-...

and the STAG-50: amb...

So far so good. Now come the questions

What would be the best strategy to run this system in combination with the Holley HP EFI system? Is there any way that I can keep all the brains and all the functionality of the HP EFI and "simply" switch off the gasoline injectors and "simply" switch on/open the LPG servo?

What is the best way of doing this?

What is the simplest way of achieving what I would like to have?

Thanks heaps folks for helping out!


"16th Year" Gold Supporting Member
Posts: 2005
Loc: Dallas, TX
Reg: 05-17-04
04-22-18 11:30 AM - Post#2731870    
    In response to AMWRX

You might have better luck with answers on the Holley Performance products Forum.

'57 210, 327 cid, Holley MPFI, 700R4, A/C & more.
'51 Studebaker Starlite coupe, 350, TH400, GV OD.
'96 Replica of a 1950's Teardrop Trailer.

Senior Member
Posts: 1682

Loc: Whitewater, CO
Reg: 05-25-01
04-22-18 12:41 PM - Post#2731876    
    In response to 5Larry7

I dont really think that it is worth it.

What I think would be worth it is....


So....that would be a 4L60, or 4L80, or Gear Vendors, or ?

Or just a plain ole everyday axle ratio change. What ratio do you have now?

Edited by Stinky on 04-22-18 12:44 PM. Reason for edit: No reason given.

Posts: 54

Age: 60
Loc: South Africa
Reg: 06-26-12
04-25-18 02:16 PM - Post#2732187    
    In response to Stinky

It is well worth it - the LPG system is not expensive and I have a used tank here that fits - It'll be few thousand miles for breaking even. But thanks for the suggestions.

There must be a way for the HP EFI computer to simply "switch" from the fuel injectors to that servo valve. That is really all the magic that is required.

LPG has another advantage: you won't have that annoying unburnt hydrocarbon smell around the car.

Hope I can find a solution...

Posts: 54

Age: 60
Loc: South Africa
Reg: 06-26-12
05-26-18 08:31 AM - Post#2734951    
    In response to AMWRX

as suggested, here the same topic in the holley forum


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