What heads should I use on a 427
11-25-2014, 04:29 PM
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What heads should I use on a 427 *Plans changed. I got a great deal on a set of 235's from TEA so I'm selling the LS2 block and going with an LSA or LS9 block for my Lunati 4" Pro Series crank and billet rods. I ordered a set of Mahle -4cc 4.070" Pistons with 1mm/1mm/2mm rings*
Last edited by drain89; 12-15-2014 at 09:34 PM.
11-25-2014, 10:08 PM
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MSD Intake looks promising is it available yet? I would run TFS LS7
Heads and have either Brian Tooley, Tony Mamo, or Chris Frank
Tune them up, Pat G. Spec the cam and definitely bore at least
4.155 if not 4.185 (unless you are going to spray beyond a 150 shot)
Heads will breathe significantly better with bigger bore with those
Large Valves. The extra 7-13 cubes will help as well. If the MSD
Intake is as good as they claim you should be able to reach 600
RWHP if you follow the advice/plan from one of the aforementioned
Experts.
Heads and have either Brian Tooley, Tony Mamo, or Chris Frank
Tune them up, Pat G. Spec the cam and definitely bore at least
4.155 if not 4.185 (unless you are going to spray beyond a 150 shot)
Heads will breathe significantly better with bigger bore with those
Large Valves. The extra 7-13 cubes will help as well. If the MSD
Intake is as good as they claim you should be able to reach 600
RWHP if you follow the advice/plan from one of the aforementioned
Experts.
11-25-2014, 11:52 PM
#4
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Most likely ERL will sleeve the block and do a 6 bolt conversion. I'd like to keep the bore closer to 4.125" so that I can re-use the block later down the road without having it re-sleeved. I also may one day choose to go forced induction so I'd like to keep cylinder walls as thick as I can to safely use a centrifugal supercharger with decent boost levels. All I'd have to do is upgrade the fuel system and put a different cam and pistons in it when I freshened up the engine.
As for heads...which of the heads mentioned offer the best geometry so I don't have to deal with worn out guides?. This is a street car so I do want some drivability and reliability while still allowing me to meet my power goals; hence why I'm not really considering a solid roller. I do understand that I will have to make compromises...but is 600 to the wheels obtainable?
With that being said...I don't need heads and a porter that gives me just great peak numbers. I want good overall flow with good velocity.
I'm basically trying to decide on what heads to use that will meet my goals and then I will talk to ALL the major cam guru's to decide what cam and what pistons to use.
E85 isn't very common around here yet, so it's really not worth it to me unless I should ever decide to go forced induction.
My local tuner is Bluecat and his dyno is very conservative. My car is an M6 and I won't go auto...so that should help when it comes time to dyno it.
Thanks for the input so far...keep it coming.
As for heads...which of the heads mentioned offer the best geometry so I don't have to deal with worn out guides?. This is a street car so I do want some drivability and reliability while still allowing me to meet my power goals; hence why I'm not really considering a solid roller. I do understand that I will have to make compromises...but is 600 to the wheels obtainable?
With that being said...I don't need heads and a porter that gives me just great peak numbers. I want good overall flow with good velocity.
I'm basically trying to decide on what heads to use that will meet my goals and then I will talk to ALL the major cam guru's to decide what cam and what pistons to use.
E85 isn't very common around here yet, so it's really not worth it to me unless I should ever decide to go forced induction.
My local tuner is Bluecat and his dyno is very conservative. My car is an M6 and I won't go auto...so that should help when it comes time to dyno it.
Thanks for the input so far...keep it coming.
11-26-2014, 12:22 AM
#5
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Is the car go be on the street more that the track or is it go be more of a track car than a street car ?
11-26-2014, 08:57 AM
#7
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Mostly Street.... I would do a big cathedral head from AFR or TFS that's touched up by a guru. Let's be honest here most real street cars live life under 6500 rpm. Right? According to Brian Tooley and Tony Mamo both basically told me the same thing. Cathedral heads are way more explosive and responsive than a big rectangular headed motor. Peak torque comes in way sooner. Rectangle heads make tons of power up top but it's at a sacrifice on the low end....
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11-26-2014, 07:10 PM
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I agree with ChevyRunner, Square port TFS LS3 or LS7 will annihilate
Any aftermarket cathedral box to box or equivalent porting by
Brian, Tony or Chris. The runner CCs are 255 & 260 respectively,
Not that much bigger than 245,255 AFR or TFS catthedral.
The exhaust flow % are much closer to cathedrals as well 70%+
versus 60%+ for factory square ports even after porting.
This means exhaust split can be +6-8* vs 12-16* or more which is why the
Square ports get a bad rap for low speed torque and throttle response
IMO. Not only that but a FAST 102 cathedral chokes off even the best
Flowing cathedral heads by 30+ CFM per runner compared to the
FAST LS3,LS7 intakes. I also am interested in the MSD Intake and plan to
Compare W/ a Ported FAST 102 LS3 intake for my build.
My TFS LS3 Heads, touched-up by a vendor who wishes to remain
Anonymous, flowed 302CFM @ .400, 350CFM @ .500, 386CFM @ .600
On a 4.155 Bore (I am using a 4.195 Bore) and flowed a few CFM
BETTER VS 4.060 bore at the above lifts intake & exhaust.
That is enough CFM FOR 750+ HP @ the Crank! ~ 650 ish at the wheels
In a fully optimized Manual trans car.
Also the ERL sleeves are much! Stronger than the factory sleeves and can be bored to 4.200 N/A, I would start at 4.155 (434 CI) and still have the ability to bore .010, .020, & even .030 (4.185 @ 440 CI) and with 6 bolts handle
12-15 lbs of boost ask ERL!
just my .02
Any aftermarket cathedral box to box or equivalent porting by
Brian, Tony or Chris. The runner CCs are 255 & 260 respectively,
Not that much bigger than 245,255 AFR or TFS catthedral.
The exhaust flow % are much closer to cathedrals as well 70%+
versus 60%+ for factory square ports even after porting.
This means exhaust split can be +6-8* vs 12-16* or more which is why the
Square ports get a bad rap for low speed torque and throttle response
IMO. Not only that but a FAST 102 cathedral chokes off even the best
Flowing cathedral heads by 30+ CFM per runner compared to the
FAST LS3,LS7 intakes. I also am interested in the MSD Intake and plan to
Compare W/ a Ported FAST 102 LS3 intake for my build.
My TFS LS3 Heads, touched-up by a vendor who wishes to remain
Anonymous, flowed 302CFM @ .400, 350CFM @ .500, 386CFM @ .600
On a 4.155 Bore (I am using a 4.195 Bore) and flowed a few CFM
BETTER VS 4.060 bore at the above lifts intake & exhaust.
That is enough CFM FOR 750+ HP @ the Crank! ~ 650 ish at the wheels
In a fully optimized Manual trans car.
Also the ERL sleeves are much! Stronger than the factory sleeves and can be bored to 4.200 N/A, I would start at 4.155 (434 CI) and still have the ability to bore .010, .020, & even .030 (4.185 @ 440 CI) and with 6 bolts handle
12-15 lbs of boost ask ERL!
just my .02
11-27-2014, 12:42 AM
#10
TECH Veteran
I agree with ChevyRunner, Square port TFS LS3 or LS7 will annihilate
Any aftermarket cathedral box to box or equivalent porting by
Brian, Tony or Chris. The runner CCs are 255 & 260 respectively,
Not that much bigger than 245,255 AFR or TFS catthedral.
The exhaust flow % are much closer to cathedrals as well 70%+
versus 60%+ for factory square ports even after porting.
This means exhaust split can be +6-8* vs 12-16* or more which is why the
Square ports get a bad rap for low speed torque and throttle response
IMO. Not only that but a FAST 102 cathedral chokes off even the best
Flowing cathedral heads by 30+ CFM per runner compared to the
FAST LS3,LS7 intakes. I also am interested in the MSD Intake and plan to
Compare W/ a Ported FAST 102 LS3 intake for my build.
My TFS LS3 Heads, touched-up by a vendor who wishes to remain
Anonymous, flowed 302CFM @ .400, 350CFM @ .500, 386CFM @ .600
On a 4.155 Bore (I am using a 4.195 Bore) and flowed a few CFM
BETTER VS 4.060 bore at the above lifts intake & exhaust.
That is enough CFM FOR 750+ HP @ the Crank! ~ 650 ish at the wheels
In a fully optimized Manual trans car.
Also the ERL sleeves are much! Stronger than the factory sleeves and can be bored to 4.200 N/A, I would start at 4.155 (434 CI) and still have the ability to bore .010, .020, & even .030 (4.185 @ 440 CI) and with 6 bolts handle
12-15 lbs of boost ask ERL!
just my .02
Any aftermarket cathedral box to box or equivalent porting by
Brian, Tony or Chris. The runner CCs are 255 & 260 respectively,
Not that much bigger than 245,255 AFR or TFS catthedral.
The exhaust flow % are much closer to cathedrals as well 70%+
versus 60%+ for factory square ports even after porting.
This means exhaust split can be +6-8* vs 12-16* or more which is why the
Square ports get a bad rap for low speed torque and throttle response
IMO. Not only that but a FAST 102 cathedral chokes off even the best
Flowing cathedral heads by 30+ CFM per runner compared to the
FAST LS3,LS7 intakes. I also am interested in the MSD Intake and plan to
Compare W/ a Ported FAST 102 LS3 intake for my build.
My TFS LS3 Heads, touched-up by a vendor who wishes to remain
Anonymous, flowed 302CFM @ .400, 350CFM @ .500, 386CFM @ .600
On a 4.155 Bore (I am using a 4.195 Bore) and flowed a few CFM
BETTER VS 4.060 bore at the above lifts intake & exhaust.
That is enough CFM FOR 750+ HP @ the Crank! ~ 650 ish at the wheels
In a fully optimized Manual trans car.
Also the ERL sleeves are much! Stronger than the factory sleeves and can be bored to 4.200 N/A, I would start at 4.155 (434 CI) and still have the ability to bore .010, .020, & even .030 (4.185 @ 440 CI) and with 6 bolts handle
12-15 lbs of boost ask ERL!
just my .02
Interesting facts you posted there buddy...... but I would love to see a head comparison on the 427 the op have. A big cathedral 245-255 TFS/AFR head vs the new LS3 255 cc head based off the same intake duration. I know the exhaust side will be different. ... it would be interesting to see how the curves/peaks compare to one another.
11-27-2014, 11:37 AM
#11
11-27-2014, 01:50 PM
#13
TECH Veteran
This thread is like asking do you like coke or pepsi......
I would go with a set of LS7 heads if I came across some for like 1000 bucks. A guy on here just sold some for that. Now if I had the money I would go with a big set of TFS/AFR heads. Vengeance Racing have built a lot of 427 Ci motors and PROVEN the TFS cathedral head was better to like 5500 rpm with killer torque which is fun on the street. Now with me saying that the LS7 heads will outperform the cathedral heads over 5500 rpm! 600 rwhp can be had with either head too. A 427ci with LS7 heads go need a cam in the neighborhood of 246/254 camshaft with a ported fast intake.
I would go with a set of LS7 heads if I came across some for like 1000 bucks. A guy on here just sold some for that. Now if I had the money I would go with a big set of TFS/AFR heads. Vengeance Racing have built a lot of 427 Ci motors and PROVEN the TFS cathedral head was better to like 5500 rpm with killer torque which is fun on the street. Now with me saying that the LS7 heads will outperform the cathedral heads over 5500 rpm! 600 rwhp can be had with either head too. A 427ci with LS7 heads go need a cam in the neighborhood of 246/254 camshaft with a ported fast intake.
11-27-2014, 06:22 PM
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hey man you really dont have to spend a million dollars on after market heads. you can get stock ls3 or ls7 heads and have them ported and they will flow pretty close to if not just as much as the aftermarket heads. gmhigh tech did a flow comparison of all ls3 heads, from afr to gm to procomp. they were all very close to each other. its not so much the head as it is the porting job imo
11-28-2014, 10:14 AM
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hey man you really dont have to spend a million dollars on after market heads. you can get stock ls3 or ls7 heads and have them ported and they will flow pretty close to if not just as much as the aftermarket heads. gmhigh tech did a flow comparison of all ls3 heads, from afr to gm to procomp. they were all very close to each other. its not so much the head as it is the porting job imo
Of the aftermarket rectangle port castings named so far...I like the TFS LS3/LS7and the RHS raised runner.
11-28-2014, 11:55 AM
#16
TECH Veteran
Ls3 heads seem like a hit or miss..... These car below did well (link) https://ls1tech.com/forums/vehicle-classifieds/1533547-fs-2000-camaro-ss-m6-6-0l-l92-s-500-whp-street-car.html
11-28-2014, 12:05 PM
#17
IMO, the rectangle ports are too large for a street engine under 400ci. The low RPM power suffers but good cam selection can band aid the problem and still make respectable power.
For larger engines, they are a great budget head with enough cross section to help feed the larger cubic inch engines. The LS3 port is okay, but the LS7 port is really nice. Out of the box GM LS7 castings have made more than 700hp at the flywheel naturally aspirated with a relatively small camshaft and a ported factory plastic intake.
For larger engines, they are a great budget head with enough cross section to help feed the larger cubic inch engines. The LS3 port is okay, but the LS7 port is really nice. Out of the box GM LS7 castings have made more than 700hp at the flywheel naturally aspirated with a relatively small camshaft and a ported factory plastic intake.
11-28-2014, 04:04 PM
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IMO, the rectangle ports are too large for a street engine under 400ci. The low RPM power suffers but good cam selection can band aid the problem and still make respectable power.
For larger engines, they are a great budget head with enough cross section to help feed the larger cubic inch engines. The LS3 port is okay, but the LS7 port is really nice. Out of the box GM LS7 castings have made more than 700hp at the flywheel naturally aspirated with a relatively small camshaft and a ported factory plastic intake.
For larger engines, they are a great budget head with enough cross section to help feed the larger cubic inch engines. The LS3 port is okay, but the LS7 port is really nice. Out of the box GM LS7 castings have made more than 700hp at the flywheel naturally aspirated with a relatively small camshaft and a ported factory plastic intake.
11-30-2014, 11:01 PM
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several places will take you new or used ls7 heads and rework the valve guides to get rid of the possibility of valve wobble.
American Heritage Performance does some pretty killer work on ls7's
American Heritage Performance does some pretty killer work on ls7's
12-02-2014, 09:53 PM
#20
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WCCH and several others have a solution to the guide issue. Stage 2 LS7 heads from WCCH can make big NA power, seen that. Call vendors directly and get their advise, never hurts to ask. Ported LS3, LS7, aftermarket square and cathedral port heads can get you to your goal. Be realistic about what kind of power delivery you want. IMO, a nasty high rpm motor can be less fun than a wide powerband motor 80% of the time on the street. Good luck.