l92 Pistons in a lQ4

Reply Subscribe

Thread Tools

Search this Thread

Dec 3, 2017 | 11:49 AM

71Vent

Thread Starter

Staging Lane

Joined: Nov 2016

Posts: 59

Likes: 2

l92 Pistons in a lQ4

Hello all,

I searched and can't seem to find the answer. I have a 2002 LQ4 and would like to upgrade the rods and pistons. Can I run rectangle port valve reliefs with 317 heads?
Thanks for the help!
Bill

Dec 3, 2017 | 12:03 PM

brandon6.0

TECH Addict

iTrader: (32)

Joined: Dec 2009

Posts: 2,331

Likes: 29

From: Glennville, GA.

I wanna say a 6.2 is a 376ci. A 6.0 is a 365ci with a 4.00 inch bore. A 6.0 bored .30 over is a 370ci.

So u would need to be bored a lil over .60 to fit 6.2 pistons in a 6.0 block.

Dec 3, 2017 | 12:09 PM

71Vent

Thread Starter

Staging Lane

Joined: Nov 2016

Posts: 59

Likes: 2

Thanks for the reply. I've seen some 6.0 pistols with l92 reliefs. Will the relief be in the same place or work?
thanks again

Dec 3, 2017 | 12:12 PM

NEstyle

Launching!

iTrader: (1)

Joined: Sep 2016

Posts: 264

Likes: 21

Quote:

Originally Posted by brandon6.0

I wanna say a 6.2 is a 376ci. A 6.0 is a 365ci with a 4.00 inch bore. A 6.0 bored .30 over is a 370ci.

So u would need to be bored a lil over .60 to fit 6.2 pistons in a 6.0 block.

There were 6.0s with L92 heads, though. G8s and Caprice PPVs have them.

Dec 3, 2017 | 05:29 PM

A.R. Shale Targa

11 Second Club

iTrader: (2)

Joined: Feb 2011

Posts: 3,729

Likes: 15

From: Fredonia,WI

Quote:

Originally Posted by NEstyle

There were 6.0s with L92 heads, though. G8s and Caprice PPVs have them.

LY6. IIRC
And an LQ4/9 would need to be bored .065” to fit LS3/L92/LSA sized pistons. Apparently most iron 6.0 blocks can go that far but sonic checking the cylinder thickness is a great idea before machining

Dec 3, 2017 | 05:56 PM

71Vent

Thread Starter

Staging Lane

Joined: Nov 2016

Posts: 59

Likes: 2

I'm trying to ask if I can use 6.0 pistols from an engine that uses rectangle reliefs with 317 heads.

Dec 3, 2017 | 09:07 PM

A.R. Shale Targa

11 Second Club

iTrader: (2)

Joined: Feb 2011

Posts: 3,729

Likes: 15

From: Fredonia,WI

Quote:

Originally Posted by 71Vent

I'm trying to ask if I can use 6.0 pistols from an engine that uses rectangle reliefs with 317 heads.

Same 15 degree valve angle and you’re asking if pistons having reliefs designed for 2.165” intake valves will clear heads that use a 2.0” intake valve ???

Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin

Verdad Gallardo

6 Common C5 Corvette Failures and What's Involved In Repairing Them

Pouria Savadkouei

Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph

Verdad Gallardo

Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked

Pouria Savadkouei

Top 10 Most Powerful Chevy Trucks Ever Made!

Hennessey's New Supercharged Silverado ZR2 Has 700 HP

Verdad Gallardo

Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes

Verdad Gallardo

Awesome K5 Blazer Restomod Comes With C7 Corvette Power

Verdad Gallardo

10 Camaros You Should Never Buy

10 LS Engine Myths That Refuse to Die

Verdad Gallardo

Dec 5, 2017 | 06:27 PM

clinebarger

TECH Fanatic

Joined: Jan 2015

Posts: 1,114

Likes: 33

From: Fort Worth, Texas

L92/L99 pistons have a relief for the Exhaust Valve, Not the Intake Valve. The only reason for the relief was for VVT. LS3 pistons have no reliefs.

I don't see why you couldn't run 317's with L92 pistons unless your cam is pretty radical & the PTV clearance is getting close.....In that case you would need to fly cut just about any GM production piston.

Dec 6, 2017 | 01:00 PM

#10

A.R. Shale Targa

11 Second Club

iTrader: (2)

Joined: Feb 2011

Posts: 3,729

Likes: 15

From: Fredonia,WI

Quote:

Originally Posted by 71Vent

I'm trying to ask if I can use 6.0 pistols from an engine that uses rectangle reliefs with 317 heads.

So the LY6 slugs is what you're wanting to use....
As mentioned; apparently the reliefs are for the VVT exhaust clearance and not the intake as I had thought
Most LS3 guys can cam with a 230-232 @.050" intake lobe and still clear the 2.165" valves with the factory "no reliefs" pistons
Using the 2.0" valved 317 head castings you should be good as well if keeping the intake lobe around the 230-ish

Dec 7, 2017 | 02:10 PM

#11

71Vent

Thread Starter

Staging Lane

Joined: Nov 2016

Posts: 59

Likes: 2

Thanks for all the replies. It makes sense if I use a cam that doesn't require reliefs that it won't matter.

another question.

I thought I read somewhere the older short 6.0 cranks are weaker than the gen 4s. Is this true?