How much HP does 243 heads add?

A stock pair of 243 heads can gain about 20 hp on a bolt-on LS1. Since you already have a cam, you might see a bit more. If your budget does not allow a full porting job, don’t sweat it, just swapping to 243 alone will be a big help.

When did Ls start using 243 heads?

The 243 head came on the more powerful LS6 engine from 2001 to 2006, and was used in C5 Corvettes. Later engines like the truck-spec LQ9 and LQ4 used the exact same port design as the LS6’s 243 heads, but had 6 cc larger combustion chambers.

Will 243 heads fit LS1?

Goat Herder. I got about 50 hp on my LS1 Corvette with unported 243 heads and a modest cam swap with a tune. The 243 heads flowed plenty well.

Are 243 heads better than 241?

The 243 heads as used on the LS2 motor flow at 260 CFM on the intake. LS6 243s (CNCed) with sodium filled valves flow a little better at 280 on the intake. The stock 241 head flows at 220 on the intake. Either head is a considerable improvement.

Are 706 heads better than 243 heads?

The 243 head has 2.0″ intake valves and 1.55 exh. The 706 uses 1.89 and 1.55 respectively. The 243 is an excellent head, but losing compression coupled with a larger intake valve in a tiny bore engine isn’t a good combo in comparison to the 706.

Are 5.3 and 6.0 heads the same?

You’ll lose compression if you use cathedral port 6.0 heads on your 5.3. The chamber is larger. The rectangular ports should not be used on your engine. LS6/T56 swap is complete and I’m just enjoying the time behind the wheel.

Are 241 and 243 heads the same?

The combustion chamber is a difference of 3cc smaller on the 243’s. Valve sizes are identical in both sets of heads.

Is it worth porting 706 heads?

Now, porting the 706 heads will definitely help power. We have seen ported versions of these heads from sources like Total Engine Airflow unearth flow numbers that exceed 300 cfm, so flow potential was not a problem.

What’s the difference between 241 and 243 heads?

The 243 heads flow 10 cfm more on the intake side, and like 7 cfm more on the exhaust side (if memory serves me correctly). The combustion chamber is a difference of 3cc smaller on the 243’s. Valve sizes are identical in both sets of heads.

How much horsepower can a 5.3 make?

The normally aspirated 5.3L eventually produced 503 hp at 6,600 rpm and 441 lb-ft of torque at 5,700 rpm. The new heads, cam, and intake shifted the power curve higher in the rev range, as a stock 5.3L will produce peak power at just 5,400 rpm.

How much HP can a 6.0 Chevy make?

GM 6.0L Vortec V-8 Engine Specs

Engine: General Motors 6.0L Vortec V-8 (Vortec 6000)
Emissions Equipment: Catalytic converter, positive crankcase ventilation (PCV)
Max Engine Speed: 6,000 RPM
Peak Horsepower: 360 HP @ 5,400 RPM
Peak Torque: 380 HP @ 4,200 RPM

Are 317 heads better than 706?

According to Internet folklore, the 317 heads used on the 6.0L truck engines share the intake port design with the 799 (243) heads. The 317 heads flowed more than the 706 heads by as much as 20 cfm at some lift points. The peak flow numbers differed by just 7 cfm at 0.700 lift.