6-Bolt LSX — LS3-based head porting.
Carma’s 6-bolt LSX program on the LS3 casting — 2.20″ valves, wider backcut, 412 cfm peak on our bench.
What this head actually flows.
Intake flow at 28″ — stock and ported, both measured on our own SF-1020 flow bench.
| Valve lift | Stock | Carma CNC | Gain | % |
|---|---|---|---|---|
| 0.200″ | 155 | 157 | +2 | +1% |
| 0.300″ | 222 | 231 | +9 | +4% |
| 0.400″ | 272 | 283 | +11 | +4% |
| 0.500″ | 305 | 340 | +35 | +11% |
| 0.600″ | 314 | 383 | +69 | +22% |
| 0.700″ | 303 | 407 | +104 | +34% |
Peak gain lands at 0.700″ lift: 303 CFM stock to 407 CFM ported. Low lift stays close to stock (+2 CFM at 0.200″), so the LSX LS3 keeps its street manners and makes its money up high. At 0.700″ it moves 407 CFM against 303 stock.
What we do to it.
Our full-race take on the LS3 casting: CNC port, 2.20″ intake valves, and a wider backcut valve job — 407 cfm at .700 and a 412 cfm peak at .730 lift on our SF-1020 bench. Graphed against a stock LS3 on the same bench.
Fitment and pricing.
Cars these heads come off.
- 6-bolt LSX blocks
- big-power and boosted LS3-platform builds
Valve upgrades for this head.
Offered with the port work on this platform, fitted while the heads are apart.
LSX LS3 porting, answered.
What does Carma do to 6-Bolt LSX — LS3-based heads?
Our full-race take on the LS3 casting: CNC port, 2.20″ intake valves, and a wider backcut valve job — 407 cfm at .700 and a 412 cfm peak at .730 lift on our SF-1020 bench. Graphed against a stock LS3 on the same bench.
What does 6-Bolt LSX — LS3-based head porting cost?
$1,200 for the pair of 6-Bolt LSX — LS3-based heads — both of them, CNC ported on our machine here in Nashville, and the set goes back with its own flow sheet.
Which cars does this fit?
6-bolt LSX blocks · big-power and boosted LS3-platform builds. If your combination is not listed, call us and we will tell you straight whether the head is the right move.
How much more does a ported LSX LS3 head flow?
Peak measured gain is +104 CFM at 0.700″ lift — 303 CFM stock to 407 CFM ported on our SF-1020 bench.
What should I run with ported heads?
Big cam, single/twin turbo or blower builds, forged bottom end. Heads do their best work as part of a combination, not on their own.
Other LS & LT heads we port.
The rest of the combination.
Ship them in or drop them off.
Heads can come to us on a pallet or still on the car. Tell us the combination you are building and we will tell you honestly whether porting is the right next step for it.