Correct belt, TOO SHORT, making you crazy?
I have a 1978 US X19, stumped on installing timing belt. Hints. Belt doesn't seem long enough, but I know it's correct belt.
The first time you do it, the belt feels way short and you don't see how it can ever go on properly. My first time, it took me hours, I had to give up and walk away a few times, I was almost weeping with frustration and ready to just burn the damned car...
To get the belt on:
First you need to pull the tensioner spring in the front (snail) engine mount all the way back and hold it there (visegrips on the shaft work). Then you can swing the tensioner pulley towards the snail mount and tighten the nut enough to hold it there. Chances are that you already did this as part of removing the old belt.
Then, start the new belt at the crankshaft pulley. Pull it as tight as you can before you wrap it over the aux shaft pulley, and then pull it as tight you can while wrapping it onto the camshaft pulley. You really need to pull it tight - it's really easy to get one too many teeth on the run from crank pulley to aux pulley to cam pulley, and if you do that you'll never get the damned thing on.
Now all of your remaining slack is on the back of the motor, between crank pulley and cam pulley. You will be able to just barely hook the edge of the belt over the edge of the tensioner pulley... and you twist it a bit straight and it just slips onto the tensioner. If it doesn't, start over again from the crank pulley, and get it TIGHT between crank and aux, and aux and cam this time.
Don't worry about moving the aux pulley - that just affects the distributor position, and you can correct that by rotating the dizzy when you're done. You do need to be careful to keep the cam timing mark lined up though, or the cam timing will be off and the car will run like crap.