Introducing..Summit Pro LS Forged Pistons!!!!!
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Introducing..Summit Pro LS Forged Pistons!!!!! Folks, we are proud to introduce you to our new Pro LS Forged Pistons lineup. This project has been in the works for almost a year and it's been hard not to let the cat out of the bag. First and most importantly, THEY ARE MADE IN THE USA. American Forgings, Designed, Machined, - the whole ball of wax. Heck even the rings they were designed around are 100% Made in the USA.
We've been monitoring these threads for a while and we wanted to have THE answer for every one of the questions you folks have had over the first year. We Listened and the lineup is awesome. 4.8L/5.3L/5.7L and 6.0L at this time and we'll be expanding the lineup too.
This is the best lineup of pistons ever offered. EVERY last detail was considered. Every exact CC of Dome or Dish volume was designed to give you exactly what you need without milling heads just out of necessity. Not just some lazy-cheap-to-make Flat-Tops. For this reason, there aren't a lot of flat tops....in fact the only place they made sense was the 6.0L pistons. Putting valve reliefs on a 4.8L/5.3L/5.7L flat top and you'll be leaving about 20hp worth of compression on the table. Not with Pro LS pistons. You'll find 2 and 3cc domes on the 4.8L/5.3L/5.7L pistons that gets you into the 10.5:1 range without head milling and right in the sweet spot 11 to 11.5:1 range with milling. Choose your octane folks! This is quite a gamble because people just search for "flat tops" even though they're almost always the wrong answer. We upped the compression a bit on the 5.7L LS1/LS6 and the strokers because we know you're not playing around at that point. The boost pistons target 9.5:1 for the most part.
No one...not one single piston company has every combination for Press-fit Gen. 3, Full-Floating Gen. 4, 6.125in. Aftermarket, and then 4" Stroker versions with 6.125 in. rods. Summit has done that for you. All the popular bore sizes including std. and .005" over so it's just a hone job. Anywhere we could save you money on machine work $ - we have. In fact, we even included cir-clip grooves in the press-fit pistons in case you have a set of Gen. 4 rods laying around with small-ends that need cleaned up.
What about strength? These pistons are 2618 Alloy Strutted designs with the best strength-to-weight ratio available. We maxxed-out Ring-Land thickness for you. A minimum of .275 tops on the 5.3's an .300 in. on the 5.7L and 6.0L pistons. All the domes and dishes and valve relieves and even the edge around the top have the smoothest radii possible for best combustion performance and detonation resistance. Pressure-fed pin-oiling of course. The pins that come with them are good for about 1000whp. If you are beyond that or are running a 300+ horsepower shot of nitrous...we have thick-wall 9310 Tool Steel pins available that will drop right in.
What about Power? We mentioned careful attention to the domes and dishes. We've given you valve reliefs that are adequate for almost any cam up to large Solid Rollers. We designed these pistons in conjunction with a 1.5 x 1.5 x 3.mm ring pack on the 5.3's and 1.2 x 1.2 x 3mm on the 5.7L and 6.0L. These are Steel (Plasma or Nitride depending on bore) top rings with Martensitic Ductile Napier seconds and 13lb standard-tension oils. We were very careful with the cross-sections we used through the crown...more than enough...but not too much...so the pistons are light for the power they will support. We are VERY big on getting the skirt profiles correct. The skirt taper is minimal and the break point where we start to introduce it is .120 above the bottom of a 5.430 length iron block with 4" stroke. This will support the pistons well and their skirt life will be long. We added skirt coatings too, but gave you a gauge point dot in the skirt coating to set these up with .004 in. piston-to-wall. The skirt coating is top notch and tightens clearance to .0028" net, so these forged pistons will be as quiet as they come. Don't let your machinist add .0005 or .001 to the bores...these ride absolutely fine at this clearance even with big boost or nitrous. Of course the pistons are machined extremely nicely including the positive-angle super-flat and shiny ring-grooves.
There are 73 new part numbers including oversizes and we've photo'd every one on our website so you'll know exactly what you're getting. Our instruction sheet is a full 8 1/2 x 11 of details that will keep builders out of trouble. We also put each of the 4.8L, 5.3L, 5.7L, and 6.0L sections into a catalog format. This makes it easy for engine builders to quickly determine what stroke, rod, bore and the compression ratios with 4 common chamber volumes. We've prepared a full tech article that gets into the all the tiny details that gone into giving you THE BEST piston lineup on the market.
We're attaching the master catalog here along with smaller 4.8L, 5.3L, 5.7L, and 6.0L sections separated out to make it easier to print. We hope you'll enjoy the tiny details.
Oh, you want to know the price? $499!!! It doesn't matter if it's a dome, dish, or even the lonely 6.0L flat-tops...they're all $499. What's the catch? Where does Summit price the rings? Rings with so much tech we could sell them for $200 on their own. Well we skinnied the heck out of the margins and and priced them at $99. How can we do this? Volume. We're not big on cutting corners when we have our name on the line. We're proud to present you with the only pistons that can earn the Pro LS distinction. Thank you folks for your consideration.
We've been monitoring these threads for a while and we wanted to have THE answer for every one of the questions you folks have had over the first year. We Listened and the lineup is awesome. 4.8L/5.3L/5.7L and 6.0L at this time and we'll be expanding the lineup too.
This is the best lineup of pistons ever offered. EVERY last detail was considered. Every exact CC of Dome or Dish volume was designed to give you exactly what you need without milling heads just out of necessity. Not just some lazy-cheap-to-make Flat-Tops. For this reason, there aren't a lot of flat tops....in fact the only place they made sense was the 6.0L pistons. Putting valve reliefs on a 4.8L/5.3L/5.7L flat top and you'll be leaving about 20hp worth of compression on the table. Not with Pro LS pistons. You'll find 2 and 3cc domes on the 4.8L/5.3L/5.7L pistons that gets you into the 10.5:1 range without head milling and right in the sweet spot 11 to 11.5:1 range with milling. Choose your octane folks! This is quite a gamble because people just search for "flat tops" even though they're almost always the wrong answer. We upped the compression a bit on the 5.7L LS1/LS6 and the strokers because we know you're not playing around at that point. The boost pistons target 9.5:1 for the most part.
No one...not one single piston company has every combination for Press-fit Gen. 3, Full-Floating Gen. 4, 6.125in. Aftermarket, and then 4" Stroker versions with 6.125 in. rods. Summit has done that for you. All the popular bore sizes including std. and .005" over so it's just a hone job. Anywhere we could save you money on machine work $ - we have. In fact, we even included cir-clip grooves in the press-fit pistons in case you have a set of Gen. 4 rods laying around with small-ends that need cleaned up.
What about strength? These pistons are 2618 Alloy Strutted designs with the best strength-to-weight ratio available. We maxxed-out Ring-Land thickness for you. A minimum of .275 tops on the 5.3's an .300 in. on the 5.7L and 6.0L pistons. All the domes and dishes and valve relieves and even the edge around the top have the smoothest radii possible for best combustion performance and detonation resistance. Pressure-fed pin-oiling of course. The pins that come with them are good for about 1000whp. If you are beyond that or are running a 300+ horsepower shot of nitrous...we have thick-wall 9310 Tool Steel pins available that will drop right in.
What about Power? We mentioned careful attention to the domes and dishes. We've given you valve reliefs that are adequate for almost any cam up to large Solid Rollers. We designed these pistons in conjunction with a 1.5 x 1.5 x 3.mm ring pack on the 5.3's and 1.2 x 1.2 x 3mm on the 5.7L and 6.0L. These are Steel (Plasma or Nitride depending on bore) top rings with Martensitic Ductile Napier seconds and 13lb standard-tension oils. We were very careful with the cross-sections we used through the crown...more than enough...but not too much...so the pistons are light for the power they will support. We are VERY big on getting the skirt profiles correct. The skirt taper is minimal and the break point where we start to introduce it is .120 above the bottom of a 5.430 length iron block with 4" stroke. This will support the pistons well and their skirt life will be long. We added skirt coatings too, but gave you a gauge point dot in the skirt coating to set these up with .004 in. piston-to-wall. The skirt coating is top notch and tightens clearance to .0028" net, so these forged pistons will be as quiet as they come. Don't let your machinist add .0005 or .001 to the bores...these ride absolutely fine at this clearance even with big boost or nitrous. Of course the pistons are machined extremely nicely including the positive-angle super-flat and shiny ring-grooves.
There are 73 new part numbers including oversizes and we've photo'd every one on our website so you'll know exactly what you're getting. Our instruction sheet is a full 8 1/2 x 11 of details that will keep builders out of trouble. We also put each of the 4.8L, 5.3L, 5.7L, and 6.0L sections into a catalog format. This makes it easy for engine builders to quickly determine what stroke, rod, bore and the compression ratios with 4 common chamber volumes. We've prepared a full tech article that gets into the all the tiny details that gone into giving you THE BEST piston lineup on the market.
We're attaching the master catalog here along with smaller 4.8L, 5.3L, 5.7L, and 6.0L sections separated out to make it easier to print. We hope you'll enjoy the tiny details.
Oh, you want to know the price? $499!!! It doesn't matter if it's a dome, dish, or even the lonely 6.0L flat-tops...they're all $499. What's the catch? Where does Summit price the rings? Rings with so much tech we could sell them for $200 on their own. Well we skinnied the heck out of the margins and and priced them at $99. How can we do this? Volume. We're not big on cutting corners when we have our name on the line. We're proud to present you with the only pistons that can earn the Pro LS distinction. Thank you folks for your consideration.
Last edited by Summitracing; Feb 19, 2019 at 08:03 AM.
Nice job guys. And very good price!
I won't say where these are forged, but there's really only one company out there doing forgings for everyone else. So the quality will be top notch.
I won't say where these are forged, but there's really only one company out there doing forgings for everyone else. So the quality will be top notch.
Thread Starter
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Guys, thank you for your support. This is a very big deal for us. The Pro Ls cams were the first big deal. These are the second. These parts will be viable for a very long time, so the money spent on development, capability and content is worth it in the long haul. We love physics.
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Exactly. You have rods that are capable of 850+ hp with boost. Are you staying Naturally aspirated or nitrous or going with boost? We like a fresh.005 hone to start to make the engine “new” again as long as you don’t have a serious ring ridge at the top of the cylinder. Then you’ll need to bore.
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It's a turbo car. The car is already done but wouldn't mind tearing it down at some point to put these pistons in for extra piece of mind. It's running max boost of 20psi with turbo maxed out. But plan to run a bigger turbo soon to not have to work the motor so hard.
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TECH Senior Member
Joined: Jun 2016
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From: Central Cal.
Originally Posted by G Atsma
Got that right! Cams, pistons…. I think the next step should be a nice line of heads, both cathedral and rectangular... no pressure..... lol
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Joined: Jun 2016
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From: Central Cal.
Agreed! PLUS it's quality stuff; no Chinesium or Thaitanium. Nice, reasonably-priced quality hardware! These guys are playing their A-game
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.945 pins would be SUM-326945xxxxxx
Slightly shorter pistons for 6.125 aftermarket rods are SUM-299927xxxxxx
4" stroker with aftermarket rods become SUM-110927xxxxxx
With a standard 5364 casting 70cc head, the compression on those is 9.2:1 with .045 piston to head and standard bore. If you punch it out .030 over, it goes to 9.3:1. Milling to 68cc would put it at 9.5:1.
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Exactly. You have rods that are capable of 850+ hp with boost. Are you staying Naturally aspirated or nitrous or going with boost? We like a fresh.005 hone to start to make the engine “new” again as long as you don’t have a serious ring ridge at the top of the cylinder. Then you’ll need to bore.
Thread Starter
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From: Ohio, Georgia, Nevada, Texas
Thread Starter
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Joined: Jan 2008
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From: Ohio, Georgia, Nevada, Texas
[QUOTE=zboy2012;20041307]
Any ideas on when a set for the ls3 would
be available
Let us know know what you would like to see. We have a pretty good idea, but we love feedback.
be available
Let us know know what you would like to see. We have a pretty good idea, but we love feedback.
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[QUOTE=omc8;20041470]4.100 with a LS3 would be a bit of a stretch for the bore, but some parts up to and including 4.080 would be a good idea.