Rebuilt a 79 360. Stock crank, scat rods, speed pro pistons.

Already fired up and ran for 10 minutes. Ran great. Turned her off normally, went inside and ate dinner, went out to start her back up, she started, I pushed the clutch in, she died, and now she will crank a partial turn. I can get underneath and turn it in reverse by the flywheel, and when I turn the key to crank her, she will turn a revolution, and then stop.

I pulled plugs thinking maybe a hydrolock situation, but the spark plugs are bone dry.

Swapped starters thinking maybe a bad starter, but same situation.

Before I tear my hair out, what could possibly be my issue?

Been a long week, so not gonna mess with it until morning...

Edit: oil pressure was 50psi confirmed with a mechanical gauge.

Turn it by hand forward and see what happens.

Agreed, pull the plugs back out & grab your 1&1/4" socket/breaker bar. Post what happens. EDIT After rereading I hope it is something external with the clutch (my guess) as opposed to something internal maybe with the thrust bearing (just thinking out loud).

Turning it forward by hand/1-1/4” produces the same result.

If I turn it back, and then forward, the motor eventually gets “tight” and doesn’t turn anymore.

The block was line honed, and when I assembled it, I rotated the crank every time I installed a piston. No binding at all.

Check your torque convertor bolts, sounds like one has loosened and backed out.

Did you try turning it with the plugs removed as suggested? My thought was a leaking head gasket that didn't seal and you have a cyl. full of water.

He did say he removed all the plugs and they're bone dry.

Checked flywheel bolts as I rotated the crank backwards by hand. Looking at the back of the crank flange. I can see all the bolts and that they are all the same depth.

Clutch to flywheel bolts are the same. They are all tight.

I did remove the spark plugs and they are dry, though I did not try cranking it with them removed. I was thinking that since the plugs are dry, no water present, and no hydrolock...

I will pull them again and see if it spins over freely.

Almost sounds like a standard main bearing is in place where the thrust bearing should be. But that would have been thumping I think while it was initially running.

When you get to the tight spot, does the crankshaft still have endplay?

Does it get tight, or stop? Does it always stop at the same spot (put mark on damper). May be valve stuck open hitting piston. Might pull valve covers to check.

^^^ X2!

Took valve covers off. Found these on the passenger rear (#8)

Cam and lifters are 508 Mopar Performance purple shaft. Pistons have valve reliefs. Springs are iskendarian....

Rest of the rockers look great.....

Gonna throw the borescope down this cylinder. See what I can see.

Even with plugs pulled, motor does not rotate.

Stay tuned kids!

Take a rubber mallet and give a good whack to each valve on the cylinder to see if they are free. That head is probably going to have to come off. Hopefully the piston and cylinder wall isn't damaged.

P/V collision I am thinking (sumpin dont quite add up tho). I would pull the rockers/pushrods & see if it is (now) free.

Whacked them all and they all are free.

Borescope down the cylinder shows no damage...

Ordered new pushrods and have spare rockers from another motor.

Rotated the motor by hand and the rest of the rockers and distributor cap turn, so it’s srill all connected. I have a cloyes true double roller on there....

Motor still hits when turn backwards....

^^^ & that is whith all the pushrods out?