408 crank?

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you need a 12 nut and have to grind it down 'stud n all about .025 into the nut, as in down to where you're taken .025 off the nut.

Doesn't this lose a couple threads on your highly loaded ARP nut cap?

Is this how everybody does it? Seems to me losing threads, even 1-2, is bad and worth avoiding if possible.

Should I put a tiny relief divot into the pump housing? That could save a thread maybe.

Use an ARP Bolt instead of the stud in that hole? Just a thought.
 
I thought about the ARP bolt obviously but is that what people do?

Seems to me the preload on a bolt can't ever get close to the force
to match up with the existing studs all torqued down, and it would
be the weaker side...

If it did happen, I'd feel pretty stupid. So I'm trying to avoid that feeling.
 
I thought about the ARP bolt obviously but is that what people do?

Seems to me the preload on a bolt can't ever get close to the force
to match up with the existing studs all torqued down, and it would
be the weaker side...

If it did happen, I'd feel pretty stupid. So I'm trying to avoid that feeling.

That is how mine is done and the HUGHES GIRDLE kit comes that way all studs and 1 bolt.

Bad picture but.......

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Oh yeah, where do you get that single ARP main bolt? Anybody sells singles?
 
"Ya know you hit the nail on the head. It typically takes 500 hp to put a 3000 Duster or Dart in the 12's. That's fast no matter where you are. If you can have 525-550 reliable hp there's no a lot on the street you can't whip. I'm not promoting street racing of any kind."
You're kidding, right?
You stud question was answered in the main studs thread... Me, I modify the stud (cut it), the 12pt nut (grind it), and sometimes the pump(grind it) rather than vary the faastener type. Others use bolts.
 
About the street racing? Yes. There's no beef in the webbing of a stock 360 block to accomodate the outside bolting of a four bolt main like on the race blocks. The girdle is the best bet and Hughes has a very good one. Changing the stock cast caps to ductile iron and align boring is also extra security along with rebalancing the entire rotating assembly even if its stock.
 
Well, I meant about the 500hp and 12s...lol

But on the street racing, that isnt the case where I used to hang out (Berlin Trnpk in CT). It wasnt the horsepower, but the whole package. The deadliest cars went almost as good on the pavement as they did on the track. In some cases, that was mid 10s w/spray. In one case, it was high 8s with a single turbo. My 300hp +150 NO2 plate 340 car went solid mid 12s and had one defeat in 3 years (mid-late 80s). That was when the ignition misfired due to a lose wire (at least it was to another mopar...lol. The car was not lightnig fast, but no wheel spin and dead reliable. I would jump them out of the hole and then hold them off. I loved racing big power bigblocks :).

The LA blocks, excepting the 340TA which has thicker webbing, all are not any stronger with the addition of 4-bolt caps. IMO, girdles are crutches. Just my opinion and I know what that's worth and how it differs among builders...lol Girdles are only somewhat affective in small blocks. If you really are that concerned about power over 600hp, you should be investing in a new block anyway. That's due to cost vs. return. Once you do the sonic testing, the filling, the lifter bores, purchase caps, studs, and the girdle, and then have it machined to fit... You will have spent within about $500 of a block that is MUCH better all around. The last factory block I did to the 550hp level cost $2300 four years ago. That's just the block prep: sonic tested, no girdle, no fill, 1-4 ProGram 2-bolt caps, studs, fitting/install of caps, square decked, bored, plate honed, lifter bores bushed. It's dead reliable and runs year round in CA on pump unleaded. To go to 600, I'd add the #5 cap and a short fill. With todays prices, it would be well over $3K for the block ready to asemble.
 
How close was I? 300 hp 340 with 150hp spray = 450 hp = mid 12s. Common knowledge that the 340 was always underated by at least 10%.
 
In a 3300# car that works well, to go these numbers, you need about:
mid-high 12's -320-330
12.00 - 370-380
11.50 - 420-430
11.00 - 480-490
10.70 - 520-530

In a 3000# ride, even less

My little 425hp car used to tear up the big HP braggers cars. Mostly because the big hp cars didn't make what they thought and couldn't hook what they did have.

For the OP, forged crank is the way to go on that engine.
 
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