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  #16 (permalink)  
Old 09-08-2011, 10:32 PM
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Quote:
Originally Posted by 1969chevyss
How can you tell by that view that the rod is thrown.
The valve reliefs should be aligned horizonally as viewed from the side, not twisted 45 degrees. The rod is clearly broken or very badly twisted. I'm voting on broken. This will take out the crankshaft in the process. Often the cam also gets whacked in the process and can even get broken in two or more parts, but that's of no concern for you- the cam's junk anyway.

Bottom line, if you end up w/a core block out of the deal, consider yourself lucky.

BTW- that block is good for a 0.030" overbore. Just like any other 4" nominal bore block. Many SBC blocks will sonic test OK for 0.060"- but this needs to be checked and is no way a sure thing. Always bore the least amount that will clean things up. There are 0.020", and 0.040" pistons available, too.

These blocks will crack just as easily as any other block if the block is frozen full of water, or if something finds its way into the cylinder (small nuts/bolts, etc.), for example. The blocks that would take a considerably bigger overbore were the old 265, 283 and 307 blocks- they could go 0.125" over in some cases.

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Last edited by cobalt327; 09-08-2011 at 10:39 PM.
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  #17 (permalink)  
Old 09-08-2011, 10:52 PM
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Hey we all hoping its a good block, right, if not oh well, if I have to pay a little more for a known good block oh well, i tried, the guy said he will give me my money back and he said that it did spin a bearing. Only 50 bucks
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  #18 (permalink)  
Old 09-09-2011, 02:22 PM
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Quote:
Originally Posted by 1969chevyss
Hey we all hoping its a good block, right, if not oh well, if I have to pay a little more for a known good block oh well, i tried, the guy said he will give me my money back and he said that it did spin a bearing. Only 50 bucks
$50 w/a money back guarantee is fine. As far as "spun a bearing", it did that a few miles before it threw the rod. But that's OK too- as long as the block survived.
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Old 09-10-2011, 01:28 PM
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You guys were right, the block was badly gouged inside from the rod coming apart and the piston was actually split in half, I better just go ahead and pay for a known good block, wish I had of noticed that when I got it, tried calling the guy and no answer so far, might have to go by his house and also he said it was never bored and it was 30 over, and its not a 4 bolt, its a 2 bolt, WTF! Maybe i'm starting something thats alot bigger than I can handle.
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Old 09-14-2011, 05:23 PM
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Ok now I have a known good 350 vortec block out of a 99 surburban. I will have to use an electric fuel pump, but thats ok. It is standard bore now, I plan on going 30 over with vortec heads(64cc), which came with the block also, this will be a 355 not the 383, instead of me buying just one kit I am going to buy peice by peice and get it balanced later when I have everything. Will these piston work for me, I will not be using NOS or race at the track just street driven on the weekends. The machine shop prefers to have the pistons to bore the block to the pistons I buy. http://www.summitracing.com/parts/SLP-H345ACP30/.
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  #21 (permalink)  
Old 09-14-2011, 05:46 PM
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I also am looking at these pistons also SLP-h631cp30, summit states that these will give me about 9 to 7 CR an the others are about 9 to 3.
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Old 09-14-2011, 08:11 PM
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Quote:
Originally Posted by 1969chevyss
I also am looking at these pistons also SLP-h631cp30, summit states that these will give me about 9 to 7 CR an the others are about 9 to 3.
Both the ZH631CP30 and ZH345ACP30 pistons have an advertised 5cc valve relief volume and both have the same compression height, if this is correct (the catalogs are sometimes wrong- check w/the manufacturer), the compression will be the same w/either slug.

For the money and given the plans you have for this engine, I'd use the 4 eyebrow pistons and put what I saved towards having the block torque plate honed.
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Old 09-14-2011, 08:21 PM
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Thanks for the advice, I did call the manufacturer and he told me that the 631cp30 will have a CR of 9.7 and the other 9.3. Is that such a big difference? And can I make up for better CR else where in the build?
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Old 09-14-2011, 08:28 PM
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I will check again on the compression heights and cc volume in the a.m. So far here ae the components I am leaning toward in the build so far. Guys please feel free to provide me your valuable opinion in this build because I will need evry step of the way.

Speed Pro pistons- SLP-H631CP30 OR ZH345ACP30 BOTH ARE FLAT TOP
Moly rings
Eagle 350 cast steel crank with clevite rod and main bearings
Eagle I-beam rods(press pin) with ARP bolts
I have vortec heads but later in the build I wil have the polished and rebuilt.
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Old 09-14-2011, 08:39 PM
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Quote:
Originally Posted by 1969chevyss
Thanks for the advice, I did call the manufacturer and he told me that the 631cp30 will have a CR of 9.7 and the other 9.3. Is that such a big difference? And can I make up for better CR else where in the build?
I do not know where they get those figures. With a 0.041" quench, a 0.030" over 350 SBC w/5cc relief volume pistons and a head gasket bore of 4.09" and a 64cc head chamber volume you'll have a 10.35:1 compression ratio.
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  #26 (permalink)  
Old 09-14-2011, 08:45 PM
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The quench would need to be 0.068" to be 9.7 CR. It would be 0.0865" to be 9.3 CR.
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  #27 (permalink)  
Old 09-14-2011, 08:58 PM
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Correct me if I'm wrong but I thought for a 10:1cr is the close to the nax for a street driven car. I initially wanted to be around 10:1 and I could always lower it a bit with the right cam.what would be a good cr while using pump gas. Thanks
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  #28 (permalink)  
Old 09-14-2011, 09:36 PM
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Quote:
Originally Posted by 1969chevyss
Correct me if I'm wrong but I thought for a 10:1cr is the close to the nax for a street driven car. I initially wanted to be around 10:1 and I could always lower it a bit with the right cam.what would be a good cr while using pump gas. Thanks
With iron heads I like to stay safe, about 9.5:1 suits me just fine. There are guys who run more compression (10:1'ish) than this using premium gas and iron heads like the fast burn Vortec's. Also the cam has a lot to do w/how much CR you need to have, so it's all a balancing act.

Aluminum heads tend to run cooler and will allow 1/2 to 1 point more compression.

I'm still on the fence regarding E85 fuel. While it offers good octane ratings and will support a lot higher CR, the availability in my area is zilch, and if switching over to it there are things about the carb and fuel system to be concerned with.
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  #29 (permalink)  
Old 09-14-2011, 09:46 PM
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Ok thanks for the info. I will go ahead with the Speed Pro ZH345ACP30 pistons and if need be use a thicker gasket to lower the CR. I am really grateful for your input. I will post a picture of my block when it gets back from the machine shop and keep this thread updated with my build.
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  #30 (permalink)  
Old 09-14-2011, 09:54 PM
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Quote:
Originally Posted by 1969chevyss
Ok thanks for the info. I will go ahead with the Speed Pro ZH345ACP30 pistons and if need be use a thicker gasket to lower the CR. I am really grateful for your input. I will post a picture of my block when it gets back from the machine shop and keep this thread updated with my build.
You do not want to use a thicker head gasket to control the CR. This ruins the quench distance and that can make the engine as detonation prone (or nearly so) as keeping the CR too high.

The correct way to go about this is to use a reverse dome piston w/a dish volume of about 10cc to 12cc to bring the CR down to around 9.8 to 9.6 respectively. This is figured w/a 0.041" quench. The reverse dome style piston helps to retain good turbulence- something that's often lost when using round dished pistons.
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