What is a good replacement flat top piston for a floating pin 6.0l? I have an 02 LQ9 out of an Escalade that I THOUGHT was in good shape, but it's going to need bored and new slugs put in it. Somehow water managed to get down past the knock sensor seals, rusted 7 cam lobes, some rust in 3 of the cam bearings, rusting on the cylinder walls, and I measured the cylinders to have .002-.0035 egging. My only plans for this build are a mild cam(looking at the Vinci butt kicker HL, street torker, or maybe the trucker), 1 3/4" long tube headers, 799 heads, and tbss intake. So no big power plans, basically an iron block trailblazer SS engine. I've always had good luck with sealed power and Summit has a good price on .030 over, but I also see silv-o-lite, or the super cheap enginetech's(said to be re-boxxed silv-o-lites). Or is there another route I should go for?

 

I’ve built several with all you mention. Honestly…grab what you can find right now. Parts are hard to get. I’ve built a couple of mild engines with the EngineTechs, bought through WS6Store, a vendor here. They were both 6 liter builds and have been running great for 4-5 years now. But again, grab what you can find. Lots of guys here waiting for 6-8 months for parts.

 

WS6store has some good reviews from people on here with there rebuild kits with pistons.
Also hard to go wrong with summit.

 

Thanks for the replies. My other question I have is should I stick with a plain flat top like the LQ9 was, or go to the gen 4 style with the 2 small reliefs? I didn't know if staying under .600 lift if I would benefit from the later style with the relief for PTV clearance.

 

Go with the valve reliefs. You may not need them now, but you never know, you may decide to change it up later and you will be kicking yourself if you have piston to valve clearance problems with your new combo.

 

I don’t see you needing reliefs for the cams you have mentioned. They are very mild, and with 243 heads, you shouldn’t have any issues. NOW…let’s say you get accustomed to the power in a month…just like every one of us…and you decide to throw more duration at it for power. It’s at this point that you’d wish you had got the pistons with reliefs. Me personally, I’d go with a 2 or 3cc relief if I could get them currently, just to keep from cutting reliefs later, but that’s me.

 

For my rebuild I used these high silicon 4032 pistons for street, they have valve reliefs and came with rings:
https://auto.jepistons.com/pistons-329378
Otherwise I was considering these from Summit.
https://www.summitracing.com/parts/slp-h1129cpa75mm.

 

Big difference in price. I’d go 4032 if you can swing it.

 

OP,

As you noticed we do have the SLP-H1129CPA75MM true 0cc flat tops from Sealed Power. Your compression with these would be right around 10.8:1 with a .051" head gasket. These would sit .006" in the hole with the stock 9.240" deck height. The recommended rings for these are SLP-E-921K30.

If you wanted pistons with two valve reliefs check out our Pro LS pistons. These are 2618 forged pistons. We have a 2cc flat top for the 6.0 with a 4.030" bore using the stock stroke with Gen IV .943" floating pin rods. That would be part number SUM-3269434030-2. With a .051" head gasket compression would be right around 10.6:1 with your 799 (65cc) heads. These would sit .005" in the hole with the stock 9.240" deck height. They are currently out of stock but we anticipate getting more at the end of July. We recommend our SUM-136SN9045035 file-fit rings with these pistons.

As an in-stock option, we offer the D.S.S. Racing 4032 forged pistons. They have a 5cc flat top with two valve reliefs. Those would be part number DMS-1830-4030. Your compression would be right around 10.3:1 with these pistons and a .051" head gasket. These sit .001" in the hole with the stock 9.240" deck height. You could drop to a .040" head gasket and bump that up to around 10.6:1. This would also reduce the quench distance which is good for combustion efficiency and reducing the chance of knock. The recommended rings are the D.S.S. DMS-RSDM2004030 which aren't in stock. As a substitute, you could go with the Hastings HSN-SM8565030. We don't have those in stock but Hastings does and we could have them dropshipped to you.

We looked at the cams you were thinking of. These all appear to be in the range of stage 1-2 truck cams. We have our own Pro LS line of camshafts and the "Vortec Truck Swap" cams are very popular. Take a look at our SUM-8728R1 that we've coined the "Big Truck Torkinator". Specs on it are .600/.585, 212/218, 110+3 with -5* of overlap. Another one to look at would be our SUM-8720R1 stage 2 truck high-lift cam. Specs on it are .600/.600, 218/227, 112+2 with -1* of overlap. We'd be happy to dive further into a cam recommendation if you'd like. More info on what vehicle this engine is going in, its intended use, and your goals would help fine-tune a recommendation. Info such as gear ratio and the stall speed of the converter would also be helpful.

Let us know if we can be of any further assistance. We'll be happy to help!

 

Bringing this one back to the top. Life put this on hold, but now I'm moving forward on it. My local machine shop is about 3 weeks out, so it gives me time to order pistons. I'm between the Speed Pro H1129CPA75MM or the Mahle 224-3665-0.75mm. I've had good luck in the past with speed pro pistons, but IIRC Mahle is the oem piston, and they're proven to last for a LONG time of extreme abuse. The S/P are 1.5/1.5/3mm rings vs the Mahle's 1.2/1.5/2.5mm rings. Are the Mahle's worth the extra money over the speed pro's?

 

IMO, I don't think they are worth the extra money. Those are from the aftermarket side of MAHLE The quality is going to be similar whether it's Speed Pro, SIlv-O-Lite, Engine tech or so on.

We pulled some Speed Pro's out of a motor with 30k miles that was not properly honed and you could hardly tell they were ran. I wouldnt hesitate to reuse them in something else with a new ring pack.

I ended up with Silv-O-Lites in mine because of what was available at the time about 3 years ago.

 

sorry to but in but im doing the same but my 799 heads have been milled .030 and i would like to burn regular gas 89 could i get away with the pistons your talking about with the valve cuts

 

Typically, we’d recommend starting your own thread or sending us a PM, but since this hasn’t been active since August, we don’t see any harm in continuing the discussion here. To better assist you, please share more details about your specific vehicle, engine combo, and its intended use. Cam specs are especially important to include!

 

ok i have a 2002 avalanche, not a hot rod but i want good power to tow. im putting a 6.0 in place of the 5.3. it is a 2004 6.0 stock. the heads i have i had on my 5.3 was the 799 milled ,030. i do want to run regular gas 89octane so i have the motor out and trying to get the most out of it on reg gas. I know the 799 heads are 64 cc but after .030 i dont know my cam spec are as fallowed EX
i dont know and the 6.0 has dish pistons the cam so should i replace the dish pistons with flat top and valve release. or stay and get a three layer head gasket

 

@learning101,

Thanks for the info! One thing we forgot to ask is your elevation, as it affects how much compression you can safely run with 89 octane.

If this is a stock 2004 LQ4 6.0, it likely has 6.7cc dished pistons. With your 799 heads milled 0.030" (roughly 61cc chambers) and a .051" factory head gasket, you’re around 10.5:1 compression. For towing, we’d usually recommend 93 octane at that ratio.

However, the thinner air at higher elevations allows for higher compression compared to sea level. Let us know your elevation so we can adjust accordingly!

 

imat 5500 too 6000 ft in the mountains

 

@learning101,

Thanks for the elevation info. If you're running 89 octane, we'd recommend sticking with the stock dished pistons in the LQ4 and using .051" head gaskets with the 799 heads milled .030" down to around 61cc. This setup will put you at roughly 10.5:1 static compression and 8.5:1 dynamic compression. To make the most of this combo, you'll want a good custom tune to balance performance and efficiency.

There’s room for better performance here by bumping compression. However, that would mean opening up the budget for possible forged pistons, machine work, different head gaskets, and running higher octane fuel. Let us know if you’d like to explore those options or stick with the current plan!