Hello everyone, I need a little information. I am in the process of rebuilding my 95 lt1 and have a question regarding 2 different types of standard bore pistons. I have a complete set of 8 Silvolite Non skirt pistons and a complete set of 8 Silvolite Skirted pistons. My question is this: Will i get the same compression from either or will one of them provide more compression? Thanks for any and all information.

https://www.uempistons.com/index.php...17b05e3a81ca89

https://www.uempistons.com/index.php...17b05e3a81ca89

 

???

 

The answer is in the specs, one piston gives you 8-something, the other can be ordered to give you 9-something or 10-something? The 1489h in 10.25 is closest to stock...

 

You need to be patient.... not all of us spend 24 hours on this site.

The shape of the skirt has nothing to do with the compression ratio. But if you look at the data, the second one you link has a 1cc larger valve pocket. That will lower the CR slightly. You have to do the complete CR calculation. As far as the CR they will produce, you need to do an actual calculation based on your specific engine configuration - combustion chamber cc's, gasket thickness, how deep the piston is below the deck, etc. The numbers they show are just guesses, based on their assumptions that they are installed in a totally stock engine. I suspect the two values shown for the LT1 piston are based on the difference between a normal SBC Gen 1 head combustion chamber (64cc?) and an LT1 combustion chamber (54cc). The LT1 piston appears to match the stock piston, including the ring pack dimensions.

You also need to note that the cheaper piston does not have the "H" suffix in the part number, indicating that it is simple eutectic cast aluminum, and not the hypereutectic aluminum used in the stock pistons. Simple eutectic cast aluminum is not a good choice. Note also, that if your block has been decked, you may not want the 1.540" compression height.

All of the above is offered for limited guidance only. As I have stated before.... I am not an engine builder. And, even though I think I have a pretty good grasp of what is going on, I would not, and did not, select parts for my own engine build. I let someone who is a highly experienced engine builder, with proven track record on the LT1 engine, select the parts. Yes, we talked about each choice, and they asked for my tacit approval, but I had little reason to question their choices.

 

Thanks for the input guys, i ended up going with the better pistons as well as good quality rings. Also, the guy that picked my parts is supposedly an LT guy from way back, thats why i assumed all of the parts he ordered for my build would be the best choice based upon his knowlege...That was until he ordered the wrong crank shaft to start with and then after doing some research myself did i find that he also had ordered the cheaper pistons above for my build too...Thats when i decided to dig more into it and ask for your guys input. I had already ordered the better pistons when i posted this question but just wanted to be sure before proceding. This is the second time by two different mechanics on this same car that i have had trouble getting a running motor lol. Anyways, i apologize for seeming inpatient and do appreciate and value the knowlege you guys offer....