l was driving my 1967 GTO home. It has a 400 cu. in engine with a 4 speed. l pulled into the drive way and shut it off. Two hours later l went to place it in the garage and the engine will not turn over. The starter tested great, the battery tested great. l grabbed the harmonic balancer by hand and tried to turn the crank, but had no luck...What do you think it could be?...the engine has only 45k miles on it..
During the course of searching the problem l did remove the plugs and dropped a stethiscope light down each cylinder, no water no oil. l then removed the drive line to test the tranny. It seemed OK, without removing it. l then got out my Flywheel tool, removed the inspection plate, and proceeded to turn the flywheel...Yikes! no luck there. That means the issue is in the engine.
Well, after pulling the Engine and removing the oil pan, l found that the shaft from the distributer to the oil pump had jumped out and wedged itself between the throw of the crank and the engine block. The shaft was bent real good. l found the nylon sleeve in the oil pan. In all my years building and restoring cars, l have never seen this one before.....Engine ran great for 45k and never a problem......gee wizzz
Thanx everyone for your input......Capt Ron

Thats a hi compression motor. Remove the spark plugs then try turning it over by hand. If that dont work drop the pan and see whats causing it, or if it has a solenoid try bypassing it. Not sure how u tested the starter.

pull the spark plugs out then try turning over the engine .make sure you do not have any water or fuel in cylinders causing the piston to lock.make sure trans is in neutral and clutch is disengaged

was the transmission in gear when u tried to turn the harmonic balancer? put in nuetral AND have someone depress the clutch pedal while turning the balancer. also, bench testing starters at a parts store is totally meaningless. its a manual trans car.. turn the key to the RUN position, put in second gear, have a couple helpers push it down the street & let out the clutch. does the car start or do the tires lock up???? there r a couple real simple starter ckt checks u can do, but im afraid to tell people how, when a manual trans is involved. all these tests must be done with the trans in nuetral, & the wheels blocked to prevent the car from moving

Ahhhh..Love the 1967 GTO!!!! It is one of my favorites!