High strength head bolts
- Thread starter Josh Oldenburg
- Start date
IDIBRONCO
IDIBRONCO
That's a good price from what I saw three years ago when I was looking at buying some.
I’m an arp dealer and I can’t even sell them that cheap... they must move a lot of volume
Macrobb
Full Access Member
For a 6.9, to push high power levels you'd need to up-size the bolt anyway, and going to 1/2" and then paying $$$ for ARP studs vs going to 9/16 and paying $ for bolts...
I really want to see if I can build up a 300+ RWHP 6.9, because there is more meat on the cylinder walls than a 7.3, and I have a good half-dozen of them sitting around. Including one rusted solid(good for test) and one cracked-block '84 (that's of low value otherwise)... so... Why not?
Dirtleg
Full Access Member
For a 6.9, to push high power levels you'd need to up-size the bolt anyway, and going to 1/2" and then paying $$$ for ARP studs vs going to 9/16 and paying $ for bolts...
I really want to see if I can build up a 300+ RWHP 6.9, because there is more meat on the cylinder walls than a 7.3, and I have a good half-dozen of them sitting around. Including one rusted solid(good for test) and one cracked-block '84 (that's of low value otherwise)... so... Why not?
I say go for it. I've got one (6.9) in the works that I was planning to go this route on as well. I'll be paying attention.
The key here will be getting the machining done properly. I know it will be $$$ in that regard, but I would expect anyone who could re-sleeve one of these ought to be able to drill and re-tap the head bolt bores properly.
Seems the things I've read about where they had issues were all done by hand with a drill and tap. That may be the problem right there. Not saying it couldn't be done that way by some people but I say get it done properly and no worries.
If you’re only going for 300 imo you could do that with 7/16 studs. I hardly ever build 6.9s just because the cost of drilling and tapping 34 holes you will find to be quite pricey... much cheaper to sleeve a 7.3 to a 6.9
Dirtleg
Full Access Member
In my case that would require acquiring a 7.3 block on top of the re-sleeving costs. I've already got a 6.9 block bored 40 over and pistons to match and ported 6.9 heads.
I'll attempt the resizing of the head bolts first. If that proves cost prohibitive I'll explore the 7.3 idea.
It’s definitely a lot easier to find uncracked 6.9 heads than 7.3s because of the hg design change, so it may become an even more liable option as well once 7.3 heads become more rare in good shape
Mikey89014
Full Access Member
you can buy an ARP stud kit for the 6.9 for $250.
Macrobb
Full Access Member
I have a machining degree, but no (set up) equipment to do it "right". I'm planning on rigging up a fixture, piloted drill that will follow the existing hole, and possibly using a mini drill press clamped to the block - this will cut a lot easier(and straighter if I get it all right) than a hand drill style thing.
I'm sure as heck not going to have someone else do it, cost wise. My plan is really to come up with the fixture and tooling to do it, so once I do it successfully, I can offer that as a service to others.
Also, I spoke with Justin on the subject - he tapped a block out to half inch, but found that with the studs in there you couldn't install the heads over the installed studs.
If you installed the head with two studs(or none, using the alignment sleeve things), and then installed the studs, it worked. (IIRC, he also tightened a stud down to failure, with the stud stretching well before the threads came out of the block.
Personally, I consider that to be 'good enough' - it doesn't take much of an angle for a 5" stud to be 1/8" off at 5" up, enough to cause it to not quite let the head slide down... but that same small angle would be just fine strength wise.
Dirtleg
Full Access Member
Probably less if I decide to sell mine.
Oledirtypearl86
Full Access Member
If your. Selling some 6.9 studs let me know
