27/05/2026
GM Performance LS3 Aluminium Cylinder Heads (Pair) 12629064 / 12675871 – 0821 Casting – Fully Built, With Supporting Parts
Offering for sale, due to upgrades documented here, a complete pair of 0821 LS3 GM Performance cylinder heads, fully built, with associated valve train parts & gaskets ready to bolt onto any LS engine. New gaskets also included. These much sought after 0821 cylinder heads will fit any LS motor and would be a great bolt-on upgrade or would be perfect for porting before installation to any 4.0” bore LS bottom end. The heads & all associated parts were removed from my GM Performance LS3 crate motor which has only covered 12,000 miles.
I’ve given the parts a minor clean down, but if they were put in a parts washer, I’m sure they’d come up as-new.
Cylinder head specs:
Combustion Chamber Volume: 68.4cc
Intake Port Shape: Rectangle
Intake Runner Volume: 260cc
Exhaust Port Shape: D-Port
Exhaust Runner Volume: 87cc
Intake Valve Diameter: 2.165 in
Exhaust Valve Diameter: 1.590 in
Fitted with:
BTR Platinum Dual Valve Springs (0.660” lift)
BTR locators & seals
GM Performance rockers
Also included:
NEW GM Performance head gaskets
NEW GM Performance exhaust manifold gaskets
GM 7.4” pushrods
GM Performance lifters & lifter trays
GM rocker covers
GM coil mounts
Asking price is £1,200 for the full kit of all parts listed & pictured. These cylinder heads cost over £1,000 each bare, therefore, with the BTR valve spring upgrade, new gaskets & associated parts, there is nearly £3,000 worth of parts here. Grab a bargain!
Due to their weight, buyer collects or arranges their own courier (at their own cost and risk) from B96 post code (Redditch)
