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.Colleges and new high school graduates have what I think is a strange idea. They think every freshman is an ad Colleges and new high school graduates have what I think is a strange...Our 706 & 862 ported heads include: Our in house CNC port. PCD surfaced to your desired chamber size. Proprietary competition valve job. Hand blended valve job. ***This is our most common setup, but if this doesn't meet your needs please call us so we can get you set up to your needs***. Intake valve: 2.02 Exhaust: 1.57.862 is a 5.3 liter head. Smaller combustion chamber (61.5CC), increased CR. 241 is a 5.7 liter head. Larger combustion chamber. Gains from a higher ration rocker arm (1.8 vs 1.7) are going to be minimal. Expect approximately 10 peak HP. IMO, if you have any plans of adding a aftermarket camshaft later down the road, pass on the 1.8 ratio rockers.This program works on the following head casting numbers: 243. 799. 317. 035. Now you can get this porting service on your cylinder heads at an incredibly low cost! Simply follow this procedure: Remove the cylinder heads from your car. Disassemble cylinder heads to completely bare condition.Location. Pensacola, FL. Posts. 1,263. The 243's bring about $400-450 with springs. I feel like the cathedral heads produce more low end torque compared to the LS3 heads. I dont really miss it while autocrossing, but I notice it more in daily street driving situations. The LS3 heads pull pretty hard up top.The 806 heads are literally 1st gen heads, have a perimeter bolt pattern for the valve cover. Which means you need that cover and IIRC the coil packs bolt directly on the cover vs a bracket that holds the packs together. Flow is meh even when ported. You should look for 317 or 243/799 heads with the emphasis on the later for NA builds, if going ...3712 posts · Joined 2009. #6 · Dec 4, 2009. batboy said: Think you are mixing up your facts. It's like a 25 HP gain by swapping in casting 243 (LS6/LS2) heads on a LS1. The LS2 already has the same casting heads. The only difference in the LS6 heads vs. LS2 heads are the light weight sodium filled valves.we compared 243 heads to 862 heads, ported, chamber work & big valve. let's talk tech, anyone ever see a set of stock 243 heads flow 270+ cfm? we compared 243 heads to 862 heads, ported, chamber ...862 s Vs 243 s..... 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 …which heads should I get professionally hand ported 862 or 853. I was orginally thinking of porting the 862 which are 5.3 litre heads and then. enlarging the intake valves to 2". now I'm considering just haveing the 853s done any thought and feedback is appreciated. cam-LTs-FAST78-Susp.-Rims.862 heads vs 243. The 862 casting number represents the 862 cylinder head. The 862 heads came on all LQ9 6.0 engine blocks and are completely interchangeable with the 243 cylinder head. Both the 243 and 862 heads have the same 64cc combustion chamber, but there are some very slight differences in the pore size of the two heads.This results in a slightly higher compression ratio using AFR heads. AFR: 56cc combustion chambers, smaller valves. Trick Flow: 58cc combustion chambers, larger valves. On smaller displacement engines, smaller valves and ports in AFR heads can provide better low-end torque source. The AFR 165, for example, is known for its good torque curve.The stock 5.3L heads (706 castings) flowed considerably less than the LS3 heads, by 80-90 cfm. Other differences included intake manifolds, with the LS3 being possibly the best factory LS intake ever made. By contrast, the stock (early) truck intake used on the 5.3L was likely No. 3 on the list, behind the LS3 and late-model truck (sharing the ...The LS1 debuted with 3.89-inch bores, a 3.62-inch stroke, hypereutectic aluminum flat-top pistons, a nodular iron crank, and 6.089-inch powdered metal rods. For the most part, …Jun 2, 2023 · Here’s a quick data sheet on the specs of 799 heads. Due to the similarity, 243 heads should follow the same characteristics in normal situations: Combustion chamber volume: 64.45cc. Intake port volume: 210cc (sometimes seen as 209cc too) Exhaust port volume: 75cc. Intake valve diameter: 2.00 inches.If you know how to look for heads you can buy them cheap if you know what trucks they came on. Go here and look, I have seen them as cheap as $100 a head. www.car-part.com. 2013 inferno orange ZL1 Camaro, basic mods. Pulley, injectors, mild bolt on's- 590rwhp. 11.70@122 with a six speed and a hard tire.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 ...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 aspirated engine. This ...I then went to a turbo setup, making 639 rwhp @ 8 PSI on 317 heads. I was anticipating some 10.4 second or possibly faster ET's, in good weather, with the additional 130 rwhp. Well before I got a chance to get the car to the track I blew a few pistons and rebuilt the motor with stock pistons but 317 heads in effort to lessen the horsepower some.1. 243 Livernois Stage 2 heads 2. Kook's LTs 3. Mild cam (TR 224/224 112) The gain from those 3 mods was 102 rwhp over factory. I debated the 5.3 heads vs. the 243s, was never able to come to a definite conclusion, so for the slight bump in compression I used the .040 Cometic gaskets.243 heads on 5.3l. Thread starter riccotxtre; Start date Jun 26, 2020; Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission. Jun 26, 2020 #1 R. riccotxtre TYF Newbie. Joined Jun 19, 2015 Posts 14So, casting 862 heads would do favors for your car with a perfect set up. Last Words. In a nutshell, the LS 862 heads are the best-performing, affordable, and ported 5.3 heads that will best suit your car. If you are looking for a high-performing cylinder head at an economical price, then the 862 LS heads are definitely a great choice.The intake and exhaust ports on the 243 heads are larger than those on the 799 heads, which allows for more air and fuel to enter the engine. This can result in higher horsepower and torque output. However, the smaller ports on the 799 heads can provide better velocity and airflow at lower RPMs, which can be beneficial for street-driven vehicles.For cam choices, we went right to the Comp Cams catalog and selected cam profiles designed specifically for the cathedral and rectangular-port heads. On the cathedral-port side, we chose a ...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 ...GM 706/862 5.3-Liter LS1, 218 cc. GM 243 (LS6) and 799 (LS2), 218 cc. GM 243 (LS6) and 799 (LS2), 226 cc. While not the largest name in the industry, AI is well respected. This North Carolina-based shop is practically a factory for CNC head porting, with programs for the Gen II, III, and IV small-block only.799 vs 862 heads which is better? I have a 99 5.3 that's going in my 02 silverado that currently has a 4.8 and the 5.3 has 862 heads and I found a set of 799 heads on a 5.3 in a savannah van and I was wondering what heads were better with a small cam and 75 hp shot of nitrous Reply With Quote. 10-04 ...Where the stock 243 heads featured 65cc chambers, the 317 heads featured 72 cc chambers. The 317s were given the nod over the 243 since they offered the larger chambers that most closely duplicated those on the LS3 (71cc). The biggest difference between the 317 cathedral-port heads and the LS3 heads was the port shape and …You don't need it at 500hp. A 1-7/8" tube typically runs out of room at around 1khp. Your fine. As mentioned, the gains seen from porting won't be huge. The reason is everything is already working pretty darn good as is. It would take a few more radical steps to move north on power.According to the trusty flow bench, the chamber work did indeed improve the flow rate of our 706 heads, with the largest gains coming at 0.200 lift for the intake and 0.400 lift for the exhaust ...we compared 243 heads to 862 heads, ported, chamber work & big valve. let's talk tech, anyone ever see a set of stock 243 heads flow 270+ cfm? we compared 243 heads to 862 heads, ported, chamber ...243 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 headsBrawler LS6 Style CNC Ported Cylinder Heads w/ TSP .660" Spring Kit and Titanium Retainers $ 1,835.99. PRC LS3 Aftermarket 6-Bolt 260cc CNC Cylinder Heads $ 2,709.99. Precision Race Components Aftermarket LS3 As-Cast Cylinder Heads $ 2,101.19. Precision Race Components 2014 5.3L & 6.2L CNC Porting Servicehivoltagedriver. 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.243 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 headsThe engine also had 799 or 243 casting heads which are closely related to the LS6. The engine has flex-fuel capability. In 2010, the LC9 gained VVT as well as pistons with valve reliefs, and compression dropped from 9.9 to 9.6:1. … For LC9 engine specs, read this: LC9 5.3L Engine Specs: Performance, Bore & Stroke, Cylinder Heads, Cam Specs ...We find out which factory LS head works best under boost in this back-to-back test of the 706 heads vs. the 317 heads. 398ci LS, TKX, QP 9 inch, Strange pro iron case, strange 35 spline axles, Spc front upper control arms, UMI front lower control arms, Howe ball joints, upper +.5 tall, CPP C5/6 spindles, Ridetech coilovers, C5/6 brakes, C7 x ...The 862 heads are an excellent choice for any GM vehicle with an LM7 engine. Although the design is meant for high-performance settings, it performs well in the Avalanche, Express, Silverado, Sierra, Yukon, and other trucks or SUVs from the late 1990s to about 2007. You know if you've got an LM7 engine by looking at the eighth digit of the ...Received 56 Likes on 49 Posts. Depends on the pistons and disired compression ratio, 317's and 243's are the same except for the chamber size. 317= 72cc, 243= 64cc. Reply Like. 05-16-2011, 01:20 PM. # 3. chargedc5.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?Bandaging that gnarly cut before you head to the emergency room? Snap a pic first. We’ve advised you before to take photos of your children before a big outing, screenshot your boa...Dec 16, 2010 · 87LC2. This is rarely brought up, but the combustion chamber design of the L92/Ls3 heads is superior to the 241/243 chambers. The cathedral heads use a "heart" shaped chamber where the square port heads use a "butterfly" shape. The butterfly design is said to improve tumble, swirl, flow, flame propagation, everything.Received 56 Likes on 49 Posts. Depends on the pistons and disired compression ratio, 317's and 243's are the same except for the chamber size. 317= 72cc, 243= 64cc. Reply Like. 05-16-2011, 01:20 PM. # 3. chargedc5.Casting Number 706 and 862 Head: 1999+ 4.8L / 5.3 Liter Truck Material: Aluminimum Part Number: 12559862 12561706 Combustion Chamber Volume: 61.15cc Compression Ratio: 9.5:1 Intake Port Volume: 200cc Exhaust Port Volume: 70cc Intake Valve Diameter: 1.89 inches Exhaust Valve Diameter: 1.55 inches.The 243 Heads are cast iron cylinder heads that have been CNC-machined to create larger intake and exhaust ports. The combustion chambers have also been machined to be smaller, which increases the compression ratio. While the 243 heads are not the newest or best option out there, they offer a great value for the price.TEA stage 2 862's or 243's? Jump to Latest Follow 21 - 35 of 35 Posts. 1 ...C5 Tech - LS6 valves vs stainless aftermarket in 243 heads - Curious if you guys running 243 heads keep the stock valves or replace them with aftermarket that might help flow. Looking to pick up a set of 243 heads needing hardware and work them over myself. I imagine the LS6 valves are not undercut like the stainless....400 243 190.500 275 210.600 285 216.700 288 224 Heads have fully ported exhaust, bowl ported and port matched intake, profiling of the combustion chambers and a valve job. The intake runners weren't touched, the theory being it will help with air velocity and improve torque.I'd be into the 243's for more than the "Proheader" heads which claim pretty good flow numbers and have larger SS valves. ... Had originally planned to run the 862 heads. Then found a set of 243's for $300 and figured I might as well grab them… now I found these. Save Share.