My 86 454 Conversion to Propane / Gasoline dual-fuel

[kapitein]

For those interested, heres some brief details on the recent conversion we did on my 86 454 Cali-emissions C20.

This was a voyage of discovery, often finding very weird 'stuff' that previous owners had MacGuyvered there way around.... typical for a 40yr old vehicle I suppose!

So, brief details! Where did we start? 86 C20 454 with 69k miles. From the look of everything, we are 99% certain this engine had never been open before. In the first stages of taking things apart, the carb and throttle plates looked really reallt bad, and we were worried about what we would find deeper down. But actually in the end, the internals all looked really good. The cam in particular looked peachy for the age and miles.

What did we do?

IMPCO 300A performer propane system with a 100L ring tank in place of the gasoline tank.
Custom 20L emergency/reserve gasoline tank, placed just above and infront of the rear diff against the floor of the truck
Edelbrock AVS2 650CFM carb
Edelbrock performer intake
Comp cams mild cam shaft.
Edelbrock valve covers
Hedmann ceramic coated long tubes
Custom exhaust with H-pipe and Flowmaster 40s
Electric fan conversion, with ability to run-on after ignition off.
Accel plug wires
NGK plugs
General under-hood tidy up and crap removal. Cleaning, degreasing and fault-fixing
Mini-starter (cool little thing)!
Yukon diff cover with new oil

Why a IMPCO 300A and not a 425? Because I still want the option to run on gasoline in emergencies. The 300A is the system to use if going dual-fuel. The higher capacity 425 is more suited to pure LPG motors.

The motor is tuned to run on LPG and starts/performs faultlessly. It will run and importantly also start on gasoline (retained electronic choke on minimal settings), but it doesnt run as nice as propane. This is a choice, im going to run 99% on propane, so thats what we have tuned for.

And lastly, why propane? Well im in Europe... 91 gasoline is expensive (always hovering around $9-11 gallon USD equivalent) 93 (ethanol free) is even more expensive. Propane is literally 60-75% cheaper depending on where you fill up. Its plentiful here with no supply issues. It runs clean and is cheap. So why the heck not. Set up correctly (like mine is) it runs just as nice or nicer than gasoline.

So there we are. Pics below!

Where we started, rough!

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Shiny new parts arriving!

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[kapitein]

Old cam looked great for age and miles!

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Intake valley cleaned up well!

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Header install wasnt without challenges. Chassis in the way!

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[kapitein]

Custom 20L emergency fuel tank:

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Chassis cross members needed to be slightly notched for the 100L propane ring tank.

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[kapitein]

Custom brackets for the relay system and propane condensor. Condensor is mounted longtitudinally for better performance.

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Work in progress:

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Done:

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Accel plug wires going on:

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[kapitein]

Propane filling port:

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Painting and cleaning as we go:

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Custom little coolant overflow bottle:

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Propane controller in the interior:

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[kapitein]

The finished job:

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And the electric fan

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[kapitein]

And finally, how the old gal sounds:

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[zulander]

Sounds AWESOME !! and looks great too !!