Can head studs replace head bolts will the heads are on the engine and have been torque down.

NO - you should have thought about that before you put the heads on. worst case senario, you'll crack a seal between an oil and coolant passage and or the combustion chamber and end up with oil in the water/water in the oil/or even in the combustion chamber. Although there is a chance that none of the seals will break and it works out, but how are you going to get the studs in with out messing up the threads - although some do have an extra drive head to allow this others utilize the shoulder section for installation which would be inside the head.

I've done it.. You need the ARP head studs with the allen key at the tip of the stud... You have to do it one at a time and depending on what block you have you'll have to put sealer on the threads.

But I'd leave the head bolts in anyway... I'm not a big fan of studs...

if i understand your question, you are wanting to replace a head bolt with a head stud while the head is in place and torqued... the short answer is yes. i have gone both ways with this... studs to bolts and bolts to studs but in all cases it was a war emergency and, under normal circumstances, having the head off and doing the repair properly and carefully would have been my first choice.

when using studs, you have to be certain that the stud doesnt bottom in the threads and that there are sufficient threads to transfer the load etc etc. in effect you have to say to yourself
" if this was a completely studded application, what would the studs, nuts, washers sealants and torque specs etc all look like in order to be correct and do the job "

if you can accomplish that answer then you will be fine.

i have done this job maybe 1/2 a dozen times over many years and been successful... but mostly i avoided it if i could.

Gotta' ask- why would you want to?


And Panther- what's not to like about studs?

I had a new set of ARP head bolts. The head stud come late.
I have not started the engine yet, and did not do the second torque down.

then use a snap on type stud remover that acually screws on the threads and then squeeses them to remove and install the new one and torque it and be done with it. if you have the right tool, its a no brainer.

Chris, I had the same question cross my mind... "why?"

To answer your question; I've found that on the older MK IV blocks they seem to corrode away much faster than head bolts... You can get maybe 2 seasons out of them in salt water before needing to be replaced... And if you don't catch it early enough you'll be pulling the heads and putting helicoils in the blocks...

Plus, with new MLS gaskets they're not a necessity anymore.

Makes sense. I agree on the new gaskets and the better bolts that are available now.

Us freshwater boaters don't always think about salt. I suppose if a guy really wanted to use them, they could be dry-film coated.