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Flex
06-06-2009, 08:45 PM
Hey dudes,

Anyone ever hear of a situation where the ARP head stud is too short to protrude through the head after being installed in the block? A friend sent me some pics of his heads installed on the motor with the studs being about 3/4" below the surface.

Mike Puckett
06-06-2009, 10:44 PM
It sounds like he used the ones for the bottom by the exhaust manifold on the top where the longer bolts go. :rolleyes:

Flex
06-06-2009, 11:09 PM
Mike,

No I checked. He use the 118 mm studs up top. He is telling me his block goes down about 40 mm before it is threaded for the bolts.

Mike8675309
06-07-2009, 12:06 AM
He is telling me his block goes down about 40 mm before it is threaded for the bolts.

not sure what that means. is it perhaps sitting on the guides?

Flex
06-07-2009, 02:18 PM
Mike,

What he is saying is that the holes in the block where the head bolts/studs go are not threaded to the top but go down about 1.5" before the threads start. This results in the studs being way down in the block and not being long enough to come up high enough to protrude though the head bolt bosses in the heads.

91supacoop
06-07-2009, 02:27 PM
sounds like someone may have stripped a head bolt hole, or maybe bought head bolts that were too long.
They drilled tap holes deeper, drilled clearance holes for 1.5" and then tapped down in the bottom....why they would do this is beyond me.

Where are the original head bolts that your friend pulled out?
were they longer than stock?
you should use them as a guide to see if you can get some correct length APR studs.

Flex
06-07-2009, 02:34 PM
He told me that the TTY bolts were about 140 mm beneath the heads and that he found a site selling a kit with longer long studs for 96-98 blocks, but they wanted an extra $100. I have never heard of there being a different maching for any 3.8 block, but I have also never seen a 96-98 block.

I guess he is going to have to order longer studs from ARP in order to solve his problem. I did so when I machined my brother's block to use main studs and a windage tray. Expensive but no other choice.

91supacoop
06-07-2009, 02:47 PM
OOOOOHHHHH I didn't realize it was a newer block. I guess that explains why I've never seen anything like it.

Jason Wild
06-07-2009, 03:06 PM
newer block needs longer head studs then the sc blocks

Flex
06-07-2009, 04:17 PM
Jason,

Obviously this is not news to you.

Mike8675309
06-07-2009, 06:46 PM
Yeah, if that's a late model 3.8 from a mustang, the head decks are slightly different, and the block is also slightly different. Supposed to be the strongest of the 3.8 blocks Ford Made taking what they did in the SC blocks, with things they had learned since then.

Mike Puckett
06-08-2009, 10:56 AM
That's news to me also but it makes sense concerning the problem.

XR7 Dave
06-08-2009, 01:51 PM
98+ 3.8 and all 4.2 blocks are significantly different, and the jury is out on whether or not they are any stronger or better than an SC block.

Flex
06-08-2009, 02:28 PM
98+ 3.8 and all 4.2 blocks are significantly different, and the jury is out on whether or not they are any stronger or better than an SC block.

David,

This is Josh Kessler that is having the problem with the studs. ARP apparently has 137 mm and 160 mm studs available to correct the problem.

Poor kid just spent a week trying to port the heads and open the chambers to bring down his compression from 9.4 to 1 to something more useable. Said he managed to remove 5 cc's worth of material from the chambers. I sent him a CR formula but I don't think he input the numbers right.