How crappy are factory rods really?

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Old Nov 22, 2012 | 07:01 AM
  #1  
olds 307 and 403's Avatar
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How crappy are factory rods really?

I am really considering boring my 350 and using Probe forged pistons. I would use ARP bolts and resize. The 330 crank was balanced with 18cc Speed Pro forged pistons and factory rods. I sold the pistons and rods. I will have 350 and 403 rods to use. Do the added weight of 403 rods negate the benefits in a 350? I will be maybe using nitrous. The Probe pistons are considerbly lighter and have a taller compression height. The crank looks good to go as is, would just need cleaned and balanced. I have kept the journals oiled in my shop.
Old Nov 22, 2012 | 07:43 AM
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I always used stock 350 rods and the only problem I ever had was when it dropped a valve and turned one into a Z shape. All were used to 6200 repeatedly. Never used giggle gas tho.

It has been pounded into my head "lighter is better". I feel the SB rods are fairly strong. How much does each weigh?
Old Nov 22, 2012 | 08:20 AM
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Check the cost of rebuilding with new ARP bolts vs. aftermarket rods. For a BBO, it is about as cheap to get new rods. Also, the load on the rods is much less with modern light pistons and pins.
Old Nov 22, 2012 | 06:48 PM
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I agree, the heavier 403 rod is used because of the big-*** pistons, but how much stronger? I sure don't know.
Old Nov 22, 2012 | 06:53 PM
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The stock 350 rod is more than adequate for most builds.
Old Nov 22, 2012 | 07:53 PM
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olds 307 and 403's Avatar
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Even Bill Travato who hates them, said 400 hp in his book. Sounds decent to me. I will price out reworking rods vs the sbc set ups.
Old Nov 23, 2012 | 06:24 AM
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You'll have to factor in that your Probe pistons have Olds pins. Now if you go with sbc rods you'll need to open up the pin end.
Old Nov 23, 2012 | 06:43 AM
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How high do you want to rev, meaning how big a camshaft? For regular over 6000 excursions, I suggest pistons and pins for SBC because the pins are lighter, and buy rods for SBC. Cut the crank to fit.
Old Nov 29, 2012 | 01:43 PM
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jfb
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this is a quote from a major engine rebuilder and i personally would not push something to a breaking point. 500 flywheel horsepower for factory rods or 400 at the wheels. I always build things at least 10 to 15 percent stronger for playing room or error room.
Old Nov 29, 2012 | 03:47 PM
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Originally Posted by jfb
this is a quote from a major engine rebuilder and i personally would not push something to a breaking point. 500 flywheel horsepower for factory rods or 400 at the wheels. I always build things at least 10 to 15 percent stronger for playing room or error room.

If a rod manufacturer puts a HP rating on a set of rods, you can bet your butt that rating is very under-rated plain and simple.
Old Nov 29, 2012 | 04:25 PM
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Originally Posted by 380 Racer
If a rod manufacturer puts a HP rating on a set of rods, you can bet your butt that rating is very under-rated plain and simple.
Not only that, but it takes a LOT of cam and cylinder head to get an honest 500 HP out of a 350. Stock rods with .0025 clearance and ARP bolts will be fine.
Old Nov 30, 2012 | 07:25 PM
  #12  
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I think they will do just fine. I think sticking with my stock pistons is the route I will go. Pretty sure I will buy bare Pro Comp heads. I will mill them to 65cc. That will give me 9 to 1 on the 350, 10 to 1 on the 403 stroker. I am thinking the Lunati high efficiency 207/207 .461/.461 on 112 lsa. I will get matching springs and 1.7 roller rockers. 2200-2500 stall on the 4L60E and 700 cfm high flow tbi with the stock sbc 350 computer.
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