You didn't say if you had a toploader, you couldn't have damaged it out of the car. With the engine off, see if you can shift to all the gears. Only one lever can move at a time, when it hits neutral, then a different lever can be moved, all levers must be in neutral to begin checking. On toploaders there is a 1/4" hole that lines up for all the levers. Since you have changed the flywheel, you need to check the free play on the clutch pedal 3/4"-1 1/4" this is easiest felt using your hand and moving the clutch pedal. If you mean letting out the clutch the engine dies, the trans is locked, get all the levers to neutral. Check for a vacuum hose off, for the fast idling problem. Post your results. Good Luck.