LS7 block
Racer
Joined: Jul 2019
Posts: 384
Likes: 196
From: Jersey Shore
CF Community Team
Joined: Apr 2016
Posts: 14,158
Likes: 7,438
From: Pittsburgh
2025 C6 of the Year Finalist - Unmodified
2024 C6 of the Year Finalist - Unmodified
2023 C6 of the Year Finalist - Unmodified
2022 C6 of the Year Finalist - Unmodified
2021 C6 of the Year Finalist - Unmodified
You will need to go aftermarket, Dart, Bill Mitchell products, & RHS make aftermarket blocks
Race Director
Joined: Dec 2013
Posts: 12,502
Likes: 3,631
Yep, and if going with boost, then LSX block that you can push major boost at in the end.
The OEM LS7 block does not take well to boost, since the cylinder liners between each other are paper thin, where the boost will crack them.
The OEM LS7 block does not take well to boost, since the cylinder liners between each other are paper thin, where the boost will crack them.
Drifting
Joined: Aug 2017
Posts: 1,926
Likes: 359
From: Dayton, OH
I saw a factory block the other day. I was shocked at how thin the factory sleeves are. The block of the left is a 5.3L, not sure exactly which one. The block on the right was a 5.3L. It was bored and sleeved and is now 427 CI.
Last edited by SteveJewels; Feb 4, 2026 at 09:02 AM.
Melting Slicks
Joined: Apr 2019
Posts: 2,514
Likes: 1,167
From: Northern Wisconsin
The Gen 4 5.3 makes a good LS7 replacement block (4.125 bore, 4.000 stroke) with Darton sleeves. Just make sure you get a Gen 4 block. For some reason, the previous generation 5.3 blocks don't work out well for this, but I can't remember the reason.
