Got through an 8 hour build, added the twin carb and the steel headers, re-tuned all the valves and carbs, managed to get it half running, alignment was way out. Got it to the repair shop and gave it the full whack. Car was essentially running like perfection, got half a mile away and the piston blew, the engine caught fire and the lot just shattered.
Not using throttle axis so it's always bouncing on the limiter.
Not sure if towing it back will fix the piston, if not then it's a restart. Teleported the car to the house to get a better look.
edit: You couldn't make this crap up.
https://gyazo.com/fedc7b640c6f71333b3c1968ed147a16