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I have a 2003 GMC Sonoma 4.3l Vortex. Does anyone know if the pistons that come with it are pressed fit or floating? And if they are press fit is it possible to use the same connecting rod on a full floating piston pin??

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AFAIK all 4.3's of this era used pressed pins. Wouldn't think you could use those same rods as they have no bearing material in the hole. They are not meant to have any movement. Later floating rods have some bronze in there. They don't have to move much, but it's thousands of times per minute. With steel on steel that would create heat.
 

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You CAN use them for floaters but the small ends need to be honed. Even though lifters also ride in factory block holes, I wouldn't recommend this unless the machine shop also presses bronze bushings into the small ends. I've seen it done with no bushings, but every machinist I know recoommends against it. You lose some material from the rod end, so it's naturally not as strong.
Most pistons can be used either way. Press pins are "siezed" in the pin end due to size but the same pistons are usually fitted for wire locks for floating pins. The pins always float in the pistons.
 

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That's a good point. The pistons have to have a way to keep the pin from rubbing the cylinder wall so they have to have grooves for the retainers. Even tho all pistons float, not all have the slots machined for the locks.
 
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