If you torqued them to the yield point, get new bolts. 
LikeSorry, but clearly some people posting here have no clue how TTY bolts work, based on the posts above.
The clamping force is designed to require a specific tension in the bolt. The way you get that is to use the threads as a micrometer - once the head of the bolt has contacted the clamping surface and you've taken out the slop in the joint, turning the bolt a specific angle causes the threads to stretch the shank of the bolt by a very specific amount. This is what provides the correct clamping force - it's exactly the same concept as using a stretch gauge on rod bolts. The lube on the threads ensures that you have taken out the slop in the joint BEFORE turning the fixed angle to provide the stretch and preload. If you didn't lube the bolts, you didn't take out all that slop and thus you did NOT get the correct stretch in the bolt when you applied the fixed angle. This is NOT a properly clamped joint and the head gaskets will likely leak at some point.
The whole point I was trying to make in my first post (which was apparently lost on people) is that the good news is that the friction in the threads means that you likely did not stretch the bolts past yield the first time, which means that you could probably remove them, lube them properly, and retorque correctly without having to buy new bolts. Doing nothing is a big mistake.
Thank you for saving me the keystrokes. TTY doesn't mean they're a one-time-use, it simply means the way you achieve the proper bolt stretch uses angles, not torque.Sorry, but clearly some people posting here have no clue how TTY bolts work, based on the posts above.
The clamping force is designed to require a specific tension in the bolt. The way you get that is to use the threads as a micrometer - once the head of the bolt has contacted the clamping surface and you've taken out the slop in the joint, turning the bolt a specific angle causes the threads to stretch the shank of the bolt by a very specific amount. This is what provides the correct clamping force - it's exactly the same concept as using a stretch gauge on rod bolts. The lube on the threads ensures that you have taken out the slop in the joint BEFORE turning the fixed angle to provide the stretch and preload. If you didn't lube the bolts, you didn't take out all that slop and thus you did NOT get the correct stretch in the bolt when you applied the fixed angle. This is NOT a properly clamped joint and the head gaskets will likely leak at some point.
The whole point I was trying to make in my first post (which was apparently lost on people) is that the good news is that the friction in the threads means that you likely did not stretch the bolts past yield the first time, which means that you could probably remove them, lube them properly, and retorque correctly without having to buy new bolts. Doing nothing is a big mistake.
The OEMs have gone to TTY because it is far more accurate, which lets them shave materials in the block and heads to save weight. In older motors weight wasn't as important and the designers just make the deck surfaces thicker to spread out uneven clamping loads from torque variability. The point of a TTY fastener isn't that it's stronger. The point is that it produces a far more accurate and consistent clamping force.I get that TTY doesn’t have to mean disposable. The question is why use single use bolts on critical applications like these? I suspect the answer is it saved them 5 cents on every engine. ARP, the fastener experts, make their bolts reusable (as did all OEM for nearly a century as someone pointed out) and I have yet to encounter an application where they recommend a TTY installation protocol. If doing TTY was so much better and more accurate wouldn’t they adopt it for all their applications? I tried to get ARP main bolts but couldn’t find them for my application although I didn’t do an exhaustive search. I was able to get ARP rod bolts though thankfully and they of course are a straight up torque installation.
Mike