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 Post Posted: Mon Feb 15, 2010 5:21 pm 

Joined: Thu Jun 05, 2008 1:05 pm
Posts: 15
Location: Sagamore Hills, Ohio
I started putting my 496 together and go figure the it needs clearancing for the rods. Is this something that I can do by myself in the garage with a grinding stone or would it be better to just take the block back to the shop to have it clearanced? I know that it is possible to hit water if you go too far but I've also heard that as long as you don't take out too much and keep checking your work taking out a little bit at a time you will be fine. Is there any tips or tricks that I can use or should I just leave this for the experts?

Just a broke-ass college kid tryin to go fast

 Post Posted: Mon Feb 15, 2010 6:27 pm 
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Joined: Tue Apr 18, 2006 6:38 am
Posts: 11631
Location: Coming At Ya!
Mike I've never done a BBC but have put 4 inch stroke cranks in two SBCs and there was a bunch of material that had to be removed. I used an air grinder with a carbide burr to do that along with some of it being taken out on my milling machine. The mill made the job somewhat easier as once you cut it out to where you need it, it's pretty easy to do each of the other cylinders that same amount.

If memory serves, BBCs have a main oil gallery down next to the pan rail also so that might be something else to be concerned about.

I guess bottom line is that if there appears to be a bunch of material that has to come out and you can afford to have a "Pro" do it then I do think I'd consider that if it's not too expensive. Not saying that you can't do it but there is alot of fitting involved. I must of had my crank and rods in and out a gazillion times before I was done with my SBCs.

Big Boyz Toyz!


Necessity is the plea for every infringement of human freedom. It is the argument of tyrants; it is the creed of slaves.

William Pitt, British Prime-Minister (1759-1806)

 Post Posted: Tue Feb 16, 2010 12:07 am 

Joined: Mon Oct 22, 2007 9:33 pm
Posts: 46
Location: Chandler Arizona
Depending on the vintage of your block will have something to do with how much work your looking at.
If your block is a 454 it should already have the block relieved for the 454 stroke and rods.
If it is an earlier 427 block that may not be the case.
Regardless which one you have it should not be a problem for the average engine builder/mechanic.
I would recommend using a carbide burr as already mentioned for two reasons.
1) it will go faster.
2) the chips are lots bigger and easier to clean out.
To do the job, first install the crank with some old bearings and verify the counter balances clear the main webbing.
Grind where required.
Once the crank spins freely with a minimum of .060" clearance install a rod and piston and mark where rod bolts hit the bottom of the cylinder bore. Once your first rod and piston can clear a 360* revolution you can remove the same amount at the same location in the remaining cylinders.
After you have ground your clearances onall of the cylinders, reinstall crank and rods and verify all rods clear.
The main oil galley is on the drivers side of the block. You should have no problems grinding the clearance you need with out compromising the oil passage.
One last thing to check is your oil pan clearance once your short block is assembled. Sit pan on pan rails with a couple of bolts to hole it in place. Turn motor over to see if you have any interference problems. If your pan has the indents for the stroker cranks you should not have a problem.
Just best to check before sealing the pan on and thin hearing the clunk while setting the valves.
Best of success on your project.

Bruce Lee


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