I got a gas tank from an RC airplane, and ran the lines as shown, it’s an 11oz tank, that you can quickly refill with the fill bottle:

Here is where the tank goes, very tight fit under the engine cover, you can sorta see here, hard to get a clear view of it.

And once the gas tank was hooked up, it was time to fill it with gas, and fire up the motor. For testing pruposes the engine cover was just set in place. Also note that the twist throttle and kill switch are installed.

I made the louvered sections out of Popsicle sticks, for the sides of the guns. Made the shocks out of dowel, and cut threads into some dowel pins for the ends.

I continued work on the front wheel guns (for lack of a better term). One of the tricky parts will be making the left side gun pivot with the wheel, via a center pivot bolt and the front tie-rod will make it turn. The right side gun will be attached to the front axle, so it will already turn with the wheel. Still need to add a little more styling, tips for the barrels, slightly recessed and bumped-out lights, etc.