This photo shows 2 x 2N3055 transistors on a heat sink, lower right corner of engine bay.
Thats an Impco type gas carburetor but it is hooked up to an external hose to the bench / Filter.
The black part behind the carb is either the gas regulator or cell. ?

normally high-pressure gas from a tank is connected to a regulator which decreases pressure, which is mixes with incoming air at the carb, which has an air filter on top. 

Just more tech data.-  US Patent 3980053 contains parts list I went over carefully. There are a few proofreading mistakes and a couple parts in parts list were wrong. The Author didn't want the unit duplicated, so as some electronic parts were changed. The main UJT oscillator should be R1 Pot 25Kohm , capacitor as .006uf, R2 as 100ohm. This will give proper frequencies for operation of electrolysis circuit at 10khtz. The SCR switch is old style , mostly discontinued, and would be replaced by MOSFET on heat sink. Fast repeating DC pulses to cell is way better than straight DC for gases evolution of Hydrogen.Time is there for stuck ions to release, making faster operation. Any one interested should study the online Patent. Final output of 30volts + 200 pulse amps is sufficient for making free fuel. The approx 40 amp battery draw at 12v is replaced by standard alternator. Beefed up 450 Watts , instead of low watts CDI for an ignition coil.The magnetic field pulses also increases efficiency. Potassium Hydroxide as electrolyte allows passage of heavy current to water cell. I may replicate this also, as side project, as used at LOWERED output level, to fire just single spark plug as no separate cell, in engine.

(By the way, Archie Blue, engineer from new Zealand with Patent, also ran 2   4cyl cars on water using his special vertical cell of staggerd, perforated discs and side electrodes. Small air pimp input from cell bottom, bubbled upward, allowed the neutral air to CLEAN SWEEP the stuck ions from the thin aluminum discs. Improved Hydrogen Gas Generator efficiency. Seek and ye shall find.)

The radiation  Radiolysis Magnetron glass tube and permanent magnets schematic circuit for Mr. Horvath Patent  4107008 , 1978, is regarding the Ford V8 Fairlane conversion of water to hydrogen gas. The drawings, schematic diagram , and operation means description is there. This is what  was used. (Not nuclear Fusion apparatus which was just said for the non technical public + wild advertising) This was an update 50%  efficiency improvement over his original, earlier,  Radyolysis design, 30,000v as Patent 3954592  1976..
I just preferred his  earlier design using low voltage and pulse 200 pulse amps to small water cell.  Patent 3954592 was the change of transformer TR2 to high voltage output 30kv, instead of low voltage, the Patent 3980053 design  that I personally liked.
I took measurement from Patent, then enlarged photo with photocopier to get the actual size of the cell , based on dimensions of laminations center bar transformer TR2 core.  .The iron laminations was used of course,on the input fast high frequency ,  to be able to get higher quality DC from pulse without using heat wasting large rectifier diode.

The Nuclear fusion conversion conversation in video was wrong. That's not what it was . Just greatly improved Radiolysis of water to hydrogen + oxygen gas fuel method #3. . The#1 and #2  low + high volts designs were not shown.

Horvath had 3 established Patents on high efficiency made hydrogen gas electrical circuits. One was Magnetron glass radiation tube in water cell center. The other two were low volts out and high volts out to water cell . Two were VERY similar to your well known CDI that fires the ignition coil primary side. He beefed it up for 450Watts for the cell, while the alternator recharges battery , about 40 amps. He added efficiency measures to cell such as magnetic field and pulse flowing ions. 200A pulses to electrolysis cell at 30v DC. About 45% duty cycle cell. Designed in high frequency put to low frequency iron laminations core transformer TR2 , so as no diode needed, - called positive Critical  Wave Form. READ the Patent  on line and print it out for study later. Things were added not necessary so as to discourage others from duplication such as special machined carburetor, and separation screens for gases. The old style SCR switch is now replaced with MOSFET. The Inverter transistors as Bipolar type is replaced with Mosfet. The type Inverter is now changed to the "IC driven " type for on+ off switching of current 50% duty cycle. The oscillator frequency is adjustable which gives the wattage wanted. Three cars were converted to water, 6yl, and( 2) 4cyl engines. Hydrogen gas is the fuel of our future . Read # 3980053   1976     . Old electrical parts list was included.