What are the best heads for a ls6?
Thread Starter
Staging Lane
Joined: May 2006
Posts: 90
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What are the best heads for a ls6? Alright I am confused on which heads to go with on my ls6 motor....I have a MS3 cam and would like to get a set of heads that would give me the greatest hp/tq gains. Which ones do you guys recomend? Money isnt a factor here so whichever heads are the best I would want. 
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ET's don't have as much proven performance as AFRs. AFR's have been around for along time and put down solid number after number. The ETP heads look very promising, however, there are just not as many people running them on this board as AFRs.
Remember, with the MS3 cam you WILL have to flycut the pistons if going with the AFR's (same goes for the Darts). The ETP heads (and Trickflow I believe) have more PV clearance than stock so you will NOT have to flycut the pistons. ETP has a head with a 215 intake runner that I think would rock the **** out of the MS3 if you did not want to flycut.
That being said, if you are going to spend money on one of the best sets of heads for the LSx market, flycut your pistons yourself or pay someone to do it and go with the AFR 205s. There is a guy on here, allngn_c5, who put down 473 rwhp 431 rwtq with AFR 205s, a similar sized cam (g5x3) and a fast 90/90 setup with all the other bolt ons. I'm not saying your numbers would necessarily be that high, but you could definately get up there. I don't think I've seen an MS3 with a set of 205s yet
Remember, with the MS3 cam you WILL have to flycut the pistons if going with the AFR's (same goes for the Darts). The ETP heads (and Trickflow I believe) have more PV clearance than stock so you will NOT have to flycut the pistons. ETP has a head with a 215 intake runner that I think would rock the **** out of the MS3 if you did not want to flycut.
That being said, if you are going to spend money on one of the best sets of heads for the LSx market, flycut your pistons yourself or pay someone to do it and go with the AFR 205s. There is a guy on here, allngn_c5, who put down 473 rwhp 431 rwtq with AFR 205s, a similar sized cam (g5x3) and a fast 90/90 setup with all the other bolt ons. I'm not saying your numbers would necessarily be that high, but you could definately get up there. I don't think I've seen an MS3 with a set of 205s yet
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I would also go with a custom grind with a set of ET heads to get the max out of your motor.I have a set of ET 225 for a 3.90 bore brand new on the shelf 57cc chambers.But there 225 and there more geared for an aggressive 346 or someone that has a power adder setup.These heads N/A still will put down killer numbers.
Thread Starter
Staging Lane
Joined: May 2006
Posts: 90
Likes: 0
Wow thanks guys for the very informative information! I have been wondering what heads to go with to get the best performance out of my 346 ls6 and I think I have decided on the ET 215's. The reason I do not want to go with the afr's is because I really do not want to have to flycut my pistons just yet. Also, how much more rwhp/tq am I going to be getting out of the ET's than say the PRC LS6 stage 1 heads from texas speed? 
Originally Posted by nightmarevette
Wow thanks guys for the very informative information! I have been wondering what heads to go with to get the best performance out of my 346 ls6 and I think I have decided on the ET 215's. The reason I do not want to go with the afr's is because I really do not want to have to flycut my pistons just yet. Also, how much more rwhp/tq am I going to be getting out of the ET's than say the PRC LS6 stage 1 heads from texas speed?
Here's the deal, by electing to not fly cut, you are limiting your power potential regardless of which head you choose. Ideally, you'll want your static compression to be around 11.5:1. To get that, you'll need a 59cc chamber and a .040" head gasket.
Here's the rub, only the ET 215 and PRC 243 heads (with stock valve sizes) even have a prayer of giving you enough P to V clearance with a cam of that duration. At 59cc, I'm afraid that even those heads may not give you enough. Consider flycutting.
In a nutshell, a head with a compression advantage will often make more power than a head with a flow advantage. I would take a PRC 243 head at 59cc over an AFR 205 head at 66cc. Compression has the advantage in this case. If money is no object, then certainly you'll have the resources to flycut your pistons and run the best flowing head at the smaller combustion chamber size.
If you had no P to V clearance isssues, I would go with the head that had the best flow in the .300-.500" range. Most flow comparisons I've seen show the ET heads having the biggest advantage in this area.
Here's the rub, only the ET 215 and PRC 243 heads (with stock valve sizes) even have a prayer of giving you enough P to V clearance with a cam of that duration. At 59cc, I'm afraid that even those heads may not give you enough. Consider flycutting.
In a nutshell, a head with a compression advantage will often make more power than a head with a flow advantage. I would take a PRC 243 head at 59cc over an AFR 205 head at 66cc. Compression has the advantage in this case. If money is no object, then certainly you'll have the resources to flycut your pistons and run the best flowing head at the smaller combustion chamber size.
If you had no P to V clearance isssues, I would go with the head that had the best flow in the .300-.500" range. Most flow comparisons I've seen show the ET heads having the biggest advantage in this area.
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2013 Corvette Grand Sport A6 LME forged 416, Greg Good ported TFS 255 LS3 heads, 222/242 .629"/.604" 121LSA Pat G blower cam, ARH 1 7/8" headers, ESC Novi 1500 Supercharger w/8 rib direct drive conversion, 747rwhp/709rwtq on 93 octane, 801rwhp/735rwtq on race fuel, 10.1 @ 147.25mph 1/4 mile, 174.7mph Half Mile.
2016 Corvette Z51 M7 Magnuson Heartbeat 2300 supercharger, TSP LT headers, Pat G tuned, 667rwhp, 662rwtq, 191mph TX Mile.
2009.5 Pontiac G8 GT 6.0L, A6, AFR 230v2 heads. 506rwhp/442rwtq. 11.413 @ 121.29mph 1/4 mile, 168.7mph TX Mile
2000 Pewter Ram Air Trans Am M6 heads/cam 508 rwhp/445 rwtq SAE, 183.092 TX Mile
2022 Cadillac Escalade 6.2L A10 S&B CAI, Corsa catback.
2023 Corvette 3LT Z51 soon to be modified.
Custom LSX tuning in person or via email press here.
2013 Corvette Grand Sport A6 LME forged 416, Greg Good ported TFS 255 LS3 heads, 222/242 .629"/.604" 121LSA Pat G blower cam, ARH 1 7/8" headers, ESC Novi 1500 Supercharger w/8 rib direct drive conversion, 747rwhp/709rwtq on 93 octane, 801rwhp/735rwtq on race fuel, 10.1 @ 147.25mph 1/4 mile, 174.7mph Half Mile.
2016 Corvette Z51 M7 Magnuson Heartbeat 2300 supercharger, TSP LT headers, Pat G tuned, 667rwhp, 662rwtq, 191mph TX Mile.
2009.5 Pontiac G8 GT 6.0L, A6, AFR 230v2 heads. 506rwhp/442rwtq. 11.413 @ 121.29mph 1/4 mile, 168.7mph TX Mile
2000 Pewter Ram Air Trans Am M6 heads/cam 508 rwhp/445 rwtq SAE, 183.092 TX Mile
2022 Cadillac Escalade 6.2L A10 S&B CAI, Corsa catback.
2023 Corvette 3LT Z51 soon to be modified.
Custom LSX tuning in person or via email press here.
