I have a 71 Chevelle w/small block Gen1. this winter I pulled and detailed the engine and compartment adding Hooker headers and more Chrome including an oil pan from Summit Racing. After reassembly the Oil Pan leaked! I got a new Fel-Pro single piece oil pan gasket (GREAT PRODUCT) and replaced with the motor still in the car. I Jacked the engine up as far as I could, using a block I made, by the harmonic balancer. It took only a few minutes (30 at most) to replace the gasket and return the motor to resting on the mounts. Here I should note that I had run the car dry of fuel. When I went to start the car the battary would barely turn the motor over, I tried charging it w/ the same result. Could I have damaged something internal by supporting the engine by the Harmonic Balancer and putting pressure on the crank? I am out of ideas and am very much ready for the sale sign to go on the car.

I did that with my 327 to repleace the motor mounts and it was fine. Take a volt reading from your battery it should be around 13 to 14 volts. Right now mine reads 12.2 and it still cranks my 454 fast enough to fire the engine.

Also, check and make sure you didn't pinch or stretch any wires when you raised/lowered the engine.

It's unlikely that you damaged anything internal to the engine. Maybe, the power cable to the starter was disturbed or you got some grease on it messing up the connection.

For future reference, it is not a good idea to jack up the engine by the balancer. That can knock the balancer out of alignment, causing it to wobble. That can also result in crushing the edge of the pulley or pushing the outer ring of the balancer out of alignment with the hub. A better way to do it is jack the engine up by the oil pan, with a wood block in between the pan and the jack to protect the oil pan from punctures and dents. With the engine jacked up, put wood blocks in between the motor mounts and the frame perches to hold the engine up high. You can then pull the jack out and drop the oil pan. This method is also safer because hydraulic jacks sometimes bleed down when holding a load for a long time, potentially crushing your hands or arms or the oil pan. My buddy Wes Vann is fanatical about not trusting hydraulic jacks to hold a load over a long time.

It is unlikely anything happened internally. My guess is jacking the engine up may have snapped a ground strap possibly? Good luck.

Here I should note that I had run the car dry of fuel.

If you ran it dry try filling up the fuel bowls through the vent tube. This way you have gas right away when you try to fire it up. Post back with your results.