My 483 ci. wedge. Has 6 mild passes, not one full throttle pass on motor. Backed car out to line up and load on trailer, pulled up to ramp. Just as I started to shut it off it developed a rattle in the motor. Not a rod or lifter noise, was like something loose. Got it home and jacked up the front end. Pulled valve covers off and oil pan. Everything looks perfect, not a scratch or ding visible. Rocker arms, push rods, valves, and springs all woking and intact. Took all the plugs out and hit the starter, spun over clean and quiet. So decided to let car down and put up on blocks. Just as it was almost all the way down I heard a clink, best discrip. I can think of. Was going to turn it over by the crank and check each cyl. rockers. Put a long ratchet on it and bingo. It would not move, what ever clinked wedged somewhere and can't turn the motor either direction. Pulled the drive shaft and the trans. turns using the output shaft. And looking at the flex plate and convertor, what I can see. Nothing.
Any help on this would be deeply appreciated. Short of pulling the motor and trans I'm stumped !!!!! Help!!!!!

Try priming the engine. Could be a broken oil pickup tube.

I have no idea what the sounds would indicate , but I am fairly certain it is coming out.
Is it locked up in both directions ?
That just doesn't sound good.

Flexplate is one possibility. Check for cracks and see if it will rotate backwards 360* while checking too.

Nothing fell in from the starter area? Did you unbolt the flex plate from
the trans

Balancer locked up from rubbing on the T/C cover. Converter bolts locked against the back of the block. How was the oil pressure before problem. If it welded a bearing to the crank she can lock up tighter than a tick with no appearance of problem. Broken Cranks can to. Sorry to be the harbinger of doom, hope it is something easier.
Todd

Can't unbolt flexplate. Won't rotate. I don't use a oil pick up tube. Have a single pick up on side of oil pan. What ever it is, it's from the trans pump forward. Timing chain and gears appear to be clean and clear also.

Thank you for the reply. Oil pressure was good, about 50lbs at about 2000 rpm. The entire valve train was functioning before the little tink. And the bottom end looks perfect. Starter is intact. I thiink my first major move will be to pull the trans. I'm about 90% sure its not in the engine. But that other 10% scares me.

Flex plate bolt is my guess.
Maybe try unbolting trans some and see if it turns over .

Pull the starter and see if you can move it with a long screw driver on the
ring gear.. if not your gonna have to pull the trans(slide it off the conv
while the conv is still bolted to the engine..or pull the engine and trans
together so you can get it apart

I had to cut off a backed off convertor bolt laying on my back at Norwalk 25 years ago. I had to use a hacksaw blade holding it in my hand because it was jammed up top. Never even missed a time trial but what a pain in the butt.

Just a long shot, pull the distributor and look in there.

I'm going with converter bolt (had one stop the motor from cranking, ruined the bolt boss) or broken converter drive plate. Hopefully it's simple and cheap!

Am thinking we're on the right track. Started to remove the trans this afternoon, but at 75 yrs old pooped out. What a pain, flex plate shield, trans blanket tabs. And cutting off a bolt with a hack saw blade in hand. Not at my age. I'll break out the air tools tomorrow. Thank you everyone for your input. Will keep you informed on what I find. May have to wait till weekend if I can talk my son into helping. Thanks

I'm right behind you nearing 70.
I found that doing a little, walking away a few times during the day, you get more accomplished.
I'm sure you'll find the problem and good luck.

Mine did the same thing last fall. Thought it was a torque converter bolt. Turned out to be the jankety 440Source balancer came apart and was bouncing off the timing cover.

The motors talking to you, it saying
AKA aside those noise are a good warning, please let us know what you find

It does sound like a converter bolt issue. I always coat mine in red Loctite and try to let em cure overnight before firing the motor. That and I only use the ARP converter bolts after having issues w/ the piece of crap MP bolts that would stay tight no matter what I did.

I am betting the converter bolt is sandwiched inside the top freeze out plug on the engine.

You know you have a nephew that can come give you a hand.