The biggest problem with stretch bolts is the inconsistency. A stretch bolt from one supplier may start to stretch at 30 lbft while another from a different manufacturer may not start until 40 lbft. Then there is the amount of elasticity in the bolt once it starts to stretch. A softer bolt will stretch a lot and not apply much pressure while one that is a bit harder will apply far more pressure some of the cheaper stretch bolts have been known to snap before you get the second 90 degree turn on them. At least when you do an ARP stud up to a certain torque you know that the pressure it is exerting is going to be the same every time.
Also the problem with doing stretch bolts up to a certain torque figure is that they stretch so you've no real idea of how much pressure they are putting on the joint face. At least with the studs, you know that what your torque wrench says is what they are done up to. The other advantage is that the thread on the nut end is finer than the 5/8th UNC thread in the block so you've got far more control.
I hear you. But I can't really spend almost £200 on studs because I have already spent well over £1000 on bits, bobs and parts. I have more to go
However, I got my tub of fancy ARP grease to put on the bolts. Indie said to paste the bolts, run them down the hole and back out, then paste them again & repeat. Then, when the head is ready to put on, do it once more (a light coating each time, not blobs of it) and this will help the bolts go down and give a truer torque.
That's the theory anyway
We're at a caravan site just now and it's great apart from the locals storming past the back of the van on the wee road to the village....oh and some asshole who's dog keeps barking
The sunshine is great