Do you need to replace the head bolts when i change the head gaskets on a 90 Ford F150. I know you have to on a 3.8 but I have never heard that you have to on the 5.8.

It's always best to change them, but you can get a good idea if they are stretched by taking a small metal straight edge and laying it against the bolts if the threads are pulled you will see it.

Pitted rusted. Best way for bent lay on ground bench flat surface and roll it it will tell you straight away! And lay all

Bolts side by side if all the same use again...

you dont have to unless they are torque to yield bolts then you would have to change them

I've rebuild so many engines and use so many bolts and I've learned this, all, every single bolt stretches under torque. There is no special bolt made of a special metal that needs special treatment. If the bolt has signs that it's out of shape in any way then yes, replace it. If the cylinder head has been modified in any way then the same bolts can be use if they are still in good condition and they have been ground down in accordance with the modification done to the head. Meaning, if they shaved 1 mm off the head, then grind 1 mm off the bolt so they can accommodate. It's that simple!!!