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Showing the port work on my 862’s setup for a small 4.8 build. Goal 375-425hp at the crankshaft prior to the Turd-Bo turbo install! 👍862 castings 20022.00/...The exhaust port is a unique D-shape that improves flow. LS6 heads are the best choice only when all-out power is needed. Be prepared for a big price tag at the dealer or steep core charge from your head porter. 706 & 852 & 862 Head: 1999+ LR4 4.8-liter Truck 1999+ LM4 / LM7 5.3-liter Truck Material:Aluminum Part Number: 12559852, 12561706,12559862243 04 up LS6 aluminum center bolt 5.7 ***These castings were also used around 05 in truck applications*** 862 99 and up 4.8-5.3 Truck heads 706 99 and up 4.8-5.3 Truck heads 799 05 and up 4.8-5.3Truck heads ***reportedly came on a few corvette's too*** These are basically 243 Heads 873 99-00 LQ4 6.0 Iron center bolt headsApr 15, 2023 · The 799 head is designed and made to be compatible with high-performing LS engines, such as 4.8L, 5.3L, 5.7L, or 6.0L, etc. These vehicles require maximum airflow, making the 799 head an ideal choice. On the other hand, the 862 head is compatible with LR4, LM4, and LM7 and such engines where low torque is more essential than better horsepower.GMPP CTS-V Race lifters C5-R timing chain Improved oil pan baffle. That's it. There are some more details in my build thread, but it's basically a more durable, stock LS1 with a cam. It made 401/401 with a safe tune. It is good when the 100 treadwear tires warm up get sticky. And yes, non offset rockers from a 317 head will work on the 243 …Why are Chevy 706 Heads better than 317 or 862 Heads? 706 Heads Vs. 317 Heads; Most people tend to prefer 317 heads as they have improved ports, same as 243 and 799 Heads, which are more expensive. However, 317 heads have larger combustion chambers of 71.06cc, which will cost performance, especially on a naturally …The ideal RPM range for a camshaft on a 5.3 with 862 heads depends on various factors such as the intended use of the vehicle, the type of camshaft, the engine components, and the desired performance. Typically, a camshaft with a duration between 212-218 degrees and a lift around .550"-.600" can work well with the 5.3 engine and 862 heads.799 LS Engine Cylinder Heads are some of the most recent cylinder heads on the automotive parts market. The cylinder cast architecture is with a semi-permanent mold method. The 799 cylinder heads are in the similitude to the 2004 LS2 cylinder heads due to the triangle casting marks similarity. However, unlike the 243 heads, they do not require ...forthman. 654 posts · Joined 2003. #2 · Mar 16, 2006. The old 69-70 351w heads have bigger valves and intake runner. Otherwise the 302 and 351w heads are the same. E7TE castings are albout as good as they get. The 289 heads do offer smaller combustion chambers but also smaller intake runners. I ran 302 E7TE's ported and milled so they had ...7477 posts · Joined 2005. #5 · Jul 14, 2010. The .040" Cometic gaskets will raise compression ratio, not lower it. That said, the GM MLS gaskets seal up the best and are a decent price. I got mine from Texas Speed. Get the LS1 gaskets that are 3.910" bore diameters. That's what I used and I have no problems.The first has to do with port shape. The LS6 and the later LQ9-LQ4 heads used reshaped intake ports and D-shaped -- as opposed to oval-shaped -- exhaust ports for better flow: 200 cfm intake and 70 cfm exhaust for the 241's, and 210 intake and 75 cfm for the 243's. The second major difference is that the LS6 heads used hollow, sodium-filled ...Texas Speed & Performance is your one-stop shop for all LS and Gen 5 LT1 & LT4 performance parts and engines! We are among the largest LS and Gen 5 LT1/LT4-specific shops in the country, and we machine and assemble all of our engines, camshafts, and Precision Race Components cylinder heads in house! We also have a complete line of Texas Speed & Performance crankshafts, connecting rods, rocker ...Our fellow tech writer and dyno-flogger Richard Holdener reports a gain of roughly 15 hp with stock 5.3-liter heads on a 6.0-liter. Our 5.7-liter head test bumped the average power by 9 hp but ...The 706 Vortec heads are even slightly superior to the commonly found 862 heads. The reason is that the 706 heads are SPM ... these are basically 243 heads; See All 5 Photos. Vital Specs for 706 ...Well, I switched from the 223 to the 243. Two reasons: first, the shafts in my 223s were not the correct shafts ( too light 105g); and, second, the gapping on the the 223 made no sense with 5* difference on the scoring clubs (8 thru GW). Findings after 4 rounds. The spec for the shafts is .25 inches longer. The head is definitely smaller.Talking about cleaning heads and valves. Discussed when a valve job is needed compared to recommended. Chamfering the edges of the combustion chambers after ...The AP220SP is the biggest 23* head All-Pro has before you get into raised runner designs. It is also standard valve spacing. Flow numbers @ 28" of water. All figures in CFM. All-Pro AP220-SP-23* --- ~$3,350 (uses standard valve train and fully CNC'd runner) Intake 219cc Exhaust.862 heads: These are also compatible with 5.3 engines, 40 posts · Joined 2018. #46 · Jan 20, 2020. Your 6.0 block 863. Rectangle. 4.750" +- 0.003". 12604861. 12610716. 12675872. Share this article. We've tried to boil down the GM part numbers, casting numbers and other LS cylinder head information into an easily usable (and ideally definitive) cross reference. Note that we're not perfect and some of this data may not be perfect so use it for what you will.hivoltagedriver. Port and polish on a set of 243's is usually ~20hp. A set of ported 243's on your LS1 should make a sizable difference, especially with a cam. '09 PSM G8 GT w/ Premium & Sport packages. Go: Kooks 1 7/8" LTs, catless mids, Corsa, VCM OTRCAI, Rick C. AirRam intake and ported TB, tuned by me. 862 is a 5.3 liter head. Smaller combustion chamber (61.5CC) With that, we packed up our heads and shipped them off to Lingenfelter Performance Engineering (LPE). Lingenfelter's 243/799 CNC program opens the intake port (left) to 228cc and increases flow at .600-inch of lift to 320 cfm. The exhaust ports get opened up to 84cc, and the chambers stay at 65cc in the off-the-shelf configuration. GM 243, 799, & 317 LS2/LS6 Options: Perf

So what the difference between some milled 862s and some stock 243s? Also how big of a difference would the 243s and a nnbs intake do on a 2003 4.8?You will see 50+rwhp probably at same psi. 317/243 heads flow MUCH better than 862 truck heads. flow more at .400 lift than the 862's flow at .550 lift. Boost will also lover the bigger 2" intake valves. 243's with their smaller combustion chambers would be a better match. than the 317's.BTR HEAD GASKET - 4.8/5.3/LS1 - SOLD IN PAIRS - BTR98544. WILL NOT WORK WITH EARLY STYLE NOTCHED LS1 CYLINDER HEADS! BTR has sourced our very own MLS head gasket that can be used on 4.8, 5.3, and LS1 engines. This is a DIRECT REPLACEMENT for the LS1/LS6 GM head gaskets. This gasket has everything you know and love from the GM version: High ...After spending a very long time googling this, I've seen answers anywhere from 10.1:1 CR to 10.9:1 CR as it seems like people are calling lq9s (half a point high CR factory) lq4s and adding to the confusion. The engine is a 2005 lq4 6.0 with 317 (71 or 72 cc stock) heads and rated at a 9.4:1 CR. The 243/799 heads are 64 or 65 cc.

53 posts · Joined 2010. #4 · Nov 12, 2017. Unless you're spending money on AI ported 243's, go with the LS3's. LS3's flow more and will keep the port velocity up compared to the typical hogged to hell port jobs I've seen on factory cast heads. There are very few shops that port heads well, with AI being the best around.118. Intake valve is 2" on the 241, exhaust valve is same size as the 862. If planning on 241 heads on a 5.3 you will lose compression and hp. The Fleet... 2003 Suburban- 5.4 L59 331CI 10:5.1 Compression -Built by ME. 2004 Avalanche- 5.7 LS1 -NOT built by me. 2005 Silverado RCSB- 5.7 LS6 -Built by ME. Reply With Quote.…

Reader Q&A - also see RECOMMENDED ARTICLES & FAQs. Section 3: Understanding the Difference o. Possible cause: Also, all the heads have a new valve stem and can be replaced with new ones .