Average Machine Shop costs for the following work???
Registered User
Joined: Nov 2006
Posts: 869
From: Houston(clear lake)
We have some motors out there with 500-550hp on studded 2-bolt caps, no problems - but personally I would want to have a studded 4-bolt, splayed is a little overkill, but if you are starting with a 2-bolt block you will want to go with spayed caps because it costs the same for the machine work. You may always want more power later so I would do the conversion now so you don't have to worry at all in the future.
Registered User
Joined: May 2004
Posts: 2,001
From: Bay Area, CA
Have never had a failure due to main cap fasteners either way. Studs are much stronger, and put more clamp load on the cap keeping them from walking. OEM bolts are junk, and don't fit the threads very well - wiggle one and feel how loose it it when screwed in, that on it's own is a reason to switch to main studs that fit much better.
Registered User
Joined: Dec 1969
Posts: 1,431
From: Pacific North West
I did mine four bolt to go with the rock I put in the bottom of the block. I am coming out of the hole on a 200RWHP shot that spikes well over 750RWTQ on the hit.
When I tore down the last engine you could see the caps were walking. This was a two bolt main, ARP stud's Combo. Basic Heads cam 400RWHP with a 100 shot on top
When I tore down the last engine you could see the caps were walking. This was a two bolt main, ARP stud's Combo. Basic Heads cam 400RWHP with a 100 shot on top
Registered User
Joined: Feb 2002
Posts: 378
From: Ellensburg, WA
Also balancing the rotating assembly-Splayed 4-bolt conversion (I supplied billet caps) = $540.00
-Bore w/trq plates + Hot tank & prep & cam bearings = $260.00
- Balance Job w/Crankshaft polish = $215.00
That puts it at $1,015.00. I had some other stuff done, so give or take. Similar to what others are quoting.
Like Rich pointed out, 4-bolt main conversion isn't as straight forward as many think it is. The first block I brought to my machinist, the billet caps did not register well at all. He advised not using them period on that block. I happened to have a couple extras laying around (thanks to my addiction to boosting stock shortblocks
). The second one I brought to him fit like a glove.As far as 4-bolt necessity. That's like asking can you safely boost stock shortblocks? haha, you'll get just as many answers with different reasons.
Personally, all the engine builders I talked to warned against 2 bolts in virtually anything driven hard. They'd witnessed cap-walk in engines with as low as 400hp. So, I'd recommend talking with your machinist. And if you choose to run 2-bolt, go ahead and buy a lottery ticket while you're at it.
Registered User
Joined: Feb 2002
Posts: 378
From: Ellensburg, WA
The infamous Ellis, I failed contacting you months ago about building a 396. You have a PM.
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