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I have a 6.0 that I'm building to a 408 stroker. I just got a good deal on a set of tfs 235 heads but was told they are 4 bolt heads. I am a little slow to understanding the difference between the 4 bolt heads and 6 bolts could someone explain to me what the difference is and also if my block is a 4 or 6 bolt head?
You are good to go. Production LS/LQ engines are 4 bolt patterns.
Only the the bolt directly surrounding the the cylinder are the head bolts. The row of bolts outside the the lifters close to the valley are not considered head bolts.
A true LSX engine will have two more bolts per cylinder, one at 6 o'clock and one at 12 o'clock for 6 bolts per cylinder.
Worst case is you make enough boost to lift the heads,
Worst case is also usually north of 1400 before the 4 bolt head becomes an issue on an aftermarket head I'd say that's where I'd stop and think about a 6 bolt block/head. A lot of cash to make 1400HP though...
Ok new dilemma lol I can also get my hands on a 6 bolt set and I am thinking about that cuz in case I update the block at a later date. But someone told me and I read that it looks funny having empty holes there when you look down. Were are these holes at and anyone has pics of it? I have alot of room in my 2000 Camaro now that I got rid of alot of stuff and I dont want it looking to funny lol. Or can you only see these with the valve covers off?
I have a 6.0 that I'm building to a 408 stroker. I just got a good deal on a set of tfs 235 heads but was told they are 4 bolt heads. I am a little slow to understanding the difference between the 4 bolt heads and 6 bolts could someone explain to me what the difference is and also if my block is a 4 or 6 bolt head?
Here's a pic of a 6 bolt block attached- arrows point to the 6 mount areas.
These Chevrolet Performance LSX Bowtie engine blocks have been designed for the advanced competition engine builder. They feature Siamese cylinder bores and a semi-finished deck height. The Chevrolet Performance LSX Bowtie engine blocks can accept a maximum stroke of 4.250 in., a maximum bore of 4.250 in., and they can support displacements of 454 cu. in. or more. The blocks feature cast iron construction with a powdercoated orange finish. They accept all Gen III and IV LS-style cylinder heads, crankshafts, camshafts, and other components.
Additional features of the Chevrolet Performance Parts LSX Bowtie engine blocks include:
* Front oil feed lines that can be plugged or restricted for mechanical flat tappet or mechanical lifter applications
* Can be safely machined to 9.200 in. deck height
* 1054 Billet Steel 6-bolt main bearing caps
* 6-bolt cylinder head bolt pattern
* Cam bores that can be machined to accept 60mm roller bearings
* Can be machined for larger diameter lifters
* External oil pump feed at the rear
* Added 7th transmission bolt hole to work with early-style GM transmissions
* Can accept a front motor plate for racing use
* Threaded freeze plugs that can be used for external heaters or coolers
* Windowed main bulkhead
It is not just the matter of the size but also the matter of thread type whether it is FINE thread or COARSE thread. also, note that bolt threads have three grades of A, B, C depending how flimsy they are. The cylinder head and block are enduring Dynamic tensions and I believe D6 is a better option.
I never could understand why people would want a 6 bolt head on a 4 bolt block. The 6th bolt provision is to give better clamping especially when your going forced induction. If it's not a 6 bolt block then why bother putting a 6 bolt head on it! Your not going to gain anything from them.
I never could understand why people would want a 6 bolt head on a 4 bolt block. The 6th bolt provision is to give better clamping especially when your going forced induction. If it's not a 6 bolt block then why bother putting a 6 bolt head on it! Your not going to gain anything from them.
Many people do that........for the future when they build a new motor, most likely with boost, they already have the 6 bolt heads.
Many people do that........for the future when they build a new motor, most likely with boost, they already have the 6 bolt heads.
Like me.....
But what if you destroy that motor and those heads before you upgrade? then you wasted a set of heads. theres a highly probable chance of it too if your boosting this motor. just another thought.
Many people do that........for the future when they build a new motor, most likely with boost, they already have the 6 bolt heads.
Like me.....
Okay you plan on throwing boost on an LS block originally designed for four bolt LS heads. So explain to me what benefits there are in running the six bolt heads?
Okay you plan on throwing boost on an LS block originally designed for four bolt LS heads. So explain to me what benefits there are in running the six bolt heads?
Read this again....slowly....and get back to us...? HINT-HINT..........focus on the word FUTURE.....lol
Many people do that........for the future when they build a new motor, most likely with boost, they already have the 6 bolt heads.
But what if you destroy that motor and those heads before you upgrade? then you wasted a set of heads. theres a highly probable chance of it too if your boosting this motor. just another thought.
Read this again....slowly....and get back to us...? HINT-HINT..........focus on the word FUTURE.....lol
Many people do that........for the future when they build a new motor, most likely with boost, they already have the 6 bolt heads.
Like me.....
Dude I could care less if people want to put new six bolt heads built for their FUTURE engine onto their stock engines! My first engine part was the block and I went from there. I hope to one day in the FUTURE turbocharge my engine but I built mine for the bottle and for now it's all throttle until one day in the FUTURE I can afford to upgrade to a direct port and dedicated fuel system....
Some heads out there just happen to have 6 bolt provisions. Like the TSP as cast stuff. And maybe that's the head you want and it's in your budget and you have no intention of going deep into 4 digit hp numbers.
I don't think you'll actually find people purposely buying 6 bolt heads for 4 bolt blocks.
By the way I vote this the stupidest argument I've seen in a long time.
But what if you destroy that motor and those heads before you upgrade? then you wasted a set of heads. theres a highly probable chance of it too if your boosting this motor. just another thought.
That's possible but if you don't do things out of fear of something happening you're never gonna do ****. There's always something that can happen. Build hoping for the best.
And to throw something back at ya, what if it never pops and you bought 4 bolt heads. Now you have to buy heads again and waste money when you could have built it once.
I know a guy that bought heads 10 years ago that were too big, he's a long term dude. He just put them to use a couple of weeks ago.
Dude I could care less if people want to put new six bolt heads built for their FUTURE engine onto their stock engines! My first engine part was the block and I went from there. I hope to one day in the FUTURE turbocharge my engine but I built mine for the bottle and for now it's all throttle until one day in the FUTURE I can afford to upgrade to a direct port and dedicated fuel system....
Now you're getting it.
FUTURE......when people know they will need 6 bolt heads in the future.....they are smart to buy them and put them on their current 4 bolt block until they upgrade that block to go BIG on their next build.
Its been done to death......most people I know have 6 bolt heads on their 4 bolt blocks waiting to upgrade or already have.
04-26-2018, 09:16 AM
4 bolt or 6 bolt head 
