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Are 317 Heads Any Good?

FAQs Jackson Bowman July 31, 2022

What engines came with 317 heads?

LQ4 engines received the Generation III 317 V8 head in 2001. It has cathedral-shaped intake ports and a D-shaped exhaust. Its large combustion chamber results in lower compression ratios. Commonly used for turbo and supercharger applications.

Are 317 heads better than 706?

The 317 heads flowed up to 20 cfm more than the 706 heads at some lift points. Peak flow numbers differed by only 7 cfm at 0.700 stroke. What made the 317 heads both kissed and cursed was the size of the combustion chamber. The massive 71.5cc chamber volume puts them a full 10cc over the 706 heads.

Can a 5.3 run 317 heads?

This resulted in a 1.2 point drop in static compression (from 9.5:1 to 8.3:1). The 317 heads are often found on 5.3L turbocharged small block models, but the lack of compression really takes its toll on performance.

What LS heads are best?

The LS6 was specifically designed by GM to surpass the LS1 as the highest performing head, and it did such a good job that the “243” casting was recycled on the LS2. Aside from the LQ9, which is a copy of the LS6, these are the most powerful of the OEM cathedral ports.

What are the best heads for a 5.3 LS?

GM’s 706 Vortec heads are the cheapest and most effective heads you can get for your 5.3 liter or 4.8 liter or even some 6.0 liter LS motors.

What’s better LQ4 or LQ9?

The ONLY difference between an LQ4 and an LQ9 is the piston!

The LQ4 piston is domed while the LQ9 is a flat piston which increases compression to 10:1 and horsepower increased to 345 Factory. The LQ9 is a limited production engine and is VERY desirable as it is the HO 6.0L and has a premium price.

Are 706 heads better than 243 heads?

706 heads tend to be more popular than 243 heads with those who run naturally aspirated engines. While they don’t have the same combustion chamber size, they also don’t tend to lower the compression ratio and reduce power.

Is it worth porting 706 heads?

Well, porting the 706 heads will definitely help with power delivery. We’ve seen ported versions of these heads from sources like Total Engine Airflow revealing flow numbers in excess of 300 cfm so flow potential wasn’t an issue.

Are 706 heads better than 862?

While 862 heads are cast in sand, 706 heads are a semi-permanent mold. Also, they have smaller combustion chambers and the milling of the deck surface allows for a slightly higher compression ratio than the 706 heads. Apart from that there is only a negligible difference between 706 and 862 heads.

Are 243 heads any good?

The 243 heads deliver increased horsepower and added boost – a flow increase of up to 32.2 cfm and 28.5 cfm at the intake and exhaust ports and a horsepower increase of up to 20 horsepower. Its superior casting and better airflow along with the incredible design make it a desirable choice.

What year did 5.3 have 243 heads?

The 243 heads came on the LS6 engine, which was manufactured from 2001 to 2006. It was typically found in the C5 Corvette but was eventually ported to the LQ4 and LQ9 to meet truck specs.

What heads are on a LQ4?

The 1999-2000 LQ4 had cast iron cylinder heads. All others had aluminum heads.

How long do LS engines last?

The lifespan of the LS1 is estimated by GM at 200,000 miles. Most engines have 100,000 miles on the odometer.

How good are 862 heads?

If you ask “Are 862 heads good?” The 862 heads are pretty good because they can deliver better compression after a port. What is that? However, the cylinder heads may not flow well compared to 243 heads. Also, 706 heads are considered superior to 826 cylinder heads.

References:

  1. https://www.fulcrumparts.com/new-gm-ls-317-head-6-0l
  2. https://www.motortrend.com/how-to/surprising-hp-numbers-stock-ls-cylinder-head-test/
  3. https://www.motortrend.com/how-to/1712-surprising-hp-numbers-from-our-stock-ls-cylinder-head-test/
  4. https://www.lsenginediy.com/ultimate-ls-cathedral-port-cylinder-heads-guide/
  5. https://www.motortrend.com/features/chevy-706-ls-heads/
  6. http://bdturnkeyengines.com/60l-lq9-vs-lq4
  7. https://www.roadcartel.com/blog/are-706-heads-better-than-243-heads-2
  8. https://www.motortrend.com/how-to/ls-engine-tech-improve-flow-easy-chamber-work/
  9. https://www.alliedmotorparts.com/blogs/news/are-862-heads-a-better-choice
  10. https://www.alliedmotorparts.com/blogs/news/243-heads-all-about-243-ls-heads-their-application
  11. https://vehicletrooper.com/whats-so-special-about-243-heads/
  12. https://help.summitracing.com/app/answers/detail/a_id/4808/~/intro-to-the-lq4-and-lq9
  13. https://homex.com/ask/how-long-do-ls1-motors-last
  14. https://rxmechanic.com/862-heads/

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