Best budget LS heads
The classic budget move is swapping in better factory heads from the junkyard:
- 243 (LS6/LS2) or 799 (aluminum 5.3 trucks, the "truck 243"): the best-flowing common cathedral heads, 64–65 cc chambers. A popular upgrade for 5.3, 5.7 and 6.0 engines.
- 706 / 862 (4.8/5.3 trucks): small 61–62 cc chambers raise compression; lightly shaved 706s with a BTR Truck Norris cam made about 430 hp on Speedway's 5.3.
- 317 (iron 6.0 trucks): big 71 cc chambers, lower compression, boost-friendly.
- 823 (LS3/L92) rectangle port: much more airflow on 6.0/6.2 builds, but it needs a rectangle-port intake.
Pair any head swap with springs rated for your cam's lift, and check piston-to-valve clearance if you mill the heads.
Confidence: medium — sources disagree or are limited; check the sources below.
Related questions
- Which LS engine is best for turbo/boost?
- How much horsepower does a stock 5.3 make?
- How much horsepower can a stock 5.3 handle?
- How much boost can a stock 5.3 handle?
- Junkyard 5.3 turbo build: what do you need?
- Best cam for a 5.3
Sources
- General Motors LS-based small-block engine — Engine table — Wikipedia
- Best LS Heads for 6.0/5.3/4.8 | Cathedral Port Heads vs Rectangular — Speedway Motors
- Decoding LS Head Casting Numbers — Malex Motorsports
- Brian Tooley Racing camshaft catalog (product pages crawled 2026-09-28) — Brian Tooley Racing