I've had a preliminary search for this but struggled to find what I wanted, apologies if already covered... My Dad is working on his V8, there was an stripped spark plug so he's had an insert put in, he's now curious as to torqueing the head back up. The original torque setting is 50lbs but as it is an old engine (1939ish) which has been taken apart before is it wise to torque up to 50lbs? The concern being; stripping old bolt threads. He also doesnt want to get new bolts, he'd rather keep it original which I think alot of us can understand. So, to torque or not to torque as specified, that is the question.
If it's a Ford flathead, don't worry about the original bolts. They are better than Grade 8. Henry used good materials. A '39-ish Ford would have studs, not bolts, though.
Sorry, meant studs and if they're better than grade 8 doubtless they can take the strain. Haha, yeah yeah alright!
All of the general rules apply, clean the threads and use good assembly lube and run them down in increments of about ten pounds each round. Some head gaskets have different torque specs so check with the manufacturer and make sure they require the same 50# spec.
If you have a viable reason to suspect the block, studs, or nuts won't hold 50 ft lb of torque you better correct it. Backing off the torque isn't a good idea because you are likely to experience a head gasket leak.