If it is froze that solid, you might as well stop wasting time trying free it up.
Just pull the engine and tear it down. Most likely it will need a complete rebuild.

Agreed.....

Anything north of 140ftlbs is gonna break a hung ring and wedge between piston and wall......meaning a simple hone and re-ring just turned into a month long vacation at hotel pay for everything new.....

Wise words.....

Ill get the speed sockets out after one gentle try on Saturday - 120ftlbs MAX.

I really hope you just tear it down. IMO if and when you do get it to fire you are going to wipe that flat tappet camshaft right out because of rust in the valve train.

Its coming down
 

Last chance yesterday - got nice and warm but nothing at 140ft/lbs so manifolds off. Cranes look great and a little bit of emulsified oil - oil in sump good and not at all milky.

Exhausts show where the wet came up though so next weekend down to the bores and see whether a hone or a full teardown is in order.

Engine definitely a Gen V serial is OD725501, stamped UA on left hand bank - heads 14097088

After seeing your pictures, I wouldn't hesitate to just take it all the way down and clean up all the rust and install new bearings and rings. If it won't break lose there is a lot of rust on a couple of cylinders and I would be worried about the rings sealing. This way you are starting with a new motor and no questions in your mind. You are only talking about a couple hundred more dollars to do it right, and it's already going to be mostly apart. Sorry for your luck, but you know as a mechanic, that shortcuts usually don't turn out good. It's just another motor with a little different specs, and all you need to do is take it apart, clean it up and put it back together. Keep us posted and we can help out on the BBC.

Umm, you are going to replace those manifolds, right? And if this engine was run in saltwater, I would get the block sonic checked and consider another set of heads that have not been run in saltwater. It eats them up inside the water jackets, and all it takes is one porous spot to break through and all the thousands you spend on the rebuild is down the drain. Also, if you are planning to continue running it in saltwater, invest in a closed cooling system. Good luck!

looks like manifolds were leaking water back into the engine....thats more condensation in the exhaust ports

I've pulled motors at junkyards with less rust in the exhaust ports. I'd be pulling the heads immediately. Worst case scenario is, it's 100 pounds minimum lighter to pull.

lot of exh port rust. could be heads rotted thru at the valve guides. i would float test the heads...