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Discussion Starter #1
i'm looking for an engine rebuild kit, and here's what i found

Chevrolet: 1967-79 350, .030 in. oversized, 9.72:1 with 64cc heads, forged pistons, .010 in. rod/main bearings... Today $349.95

Chevrolet: 1967-79 350, .030 in. oversized, 9.72:1 with 64cc heads, forged pistons, .020 in. rod/main bearings... Today $349.95

what's the difference in the .010 in or .020 in?
 

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DC PIT CREW BOSS
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Don't know 100% for sure about this kit manufacturer. It is probably the amount undersize the crank journals are. If you have to have the crank ground, they will remove material at .010, .020 etc. for the rods and mains. The bearings will need to be oversize to make up for the difference the same way pistons are oversize when you bore .030 to clean and straighten a cylinder
 

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since they're the same price get the one with the .010 ground crank, you don't want a crank any thinner than that.
 

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That is an outstanding deal.
 

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kits

Personally, i do a full tear-down & inspection BEFORE I BOUGHT a kit
do you need to turn your crank? are you sure you need .030 pistons?
You might want to call a machine shop & see what they charge & remember.... they want a block & rotating assy. ONLY !! That means a COMPLEATE tear down!
 

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Discussion Starter #6
we are doing a complete tear-down and rebuild, and i already talked to the local machine shop, they charge 8 dollars a cylinder to bore, it doesn't matter if it's .030, .040 or .060 over.....so that's not a big deal, but i don't know how much they charge to ground down a crankshaft, i'm gonna try and find a kit that doesn't require me to. is there a benifit from doing it? does it make it weigh less or something?
but it'll probably be a while before i order the rebuild kit.

but yeah, i was planning on taking the engine completely apart before ordering a new kit.
 

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A machine shop will not bore the block before it has the pistons. At the same time until they check the crank you can not order a kit. Sure you could take the chance and order the undersize bearings but what if the crank it ok and only needs polishing. I prefer an unturned crank because the radius in the corner is very important. When some dress the grinding wheels they leave the corner sharper and this causes a poor radius in the corner and a weaker crank.
 

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You never buy a rebuild kit until you tear down you engine to see what you have. Piston bore my not have to bored just honed good. The crank my be fine and stock bearing my be able to be used. Only overside bearing must be used if your crank has been ground because of wear or scratches.
 

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Discussion Starter #9
why does everyone assume i was gonna by the rebuild kit before i took the engine apart?

just curious.

and i want a .030 overbore for more cubic inches.
 

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Because you talk about two different kits. only difference is the main bearing sizes. If you have already inspected the engine you would know which kit to get. you dont grind on a crank unless you have damage. and for more power try higher compression pistons not bigger O.D. then you do not have to bore the engine.
or be like everyone else and run NOS.
Run into problems myself. building a drag car. 74 stingray with 8 point roll bars. have removed the interior of the car and now installing racing seat, 5 point harness, gauges, shifter. No A/C, no heater, no radio. if it does not make this vette go faster its not in the car.
 
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