Heads Studs vs. Head Bolts

[justinp61]

My current engine has studs, it’s 11.2-1. The previous two were 10.8 and 11.4-1 and used ARP bolts. All three engines used Fel Pro 1008 head gaskets. IMO at my compression they’re all I need.

One thing I did on my current engine was after installing the heads I let it sit overnight. The next day I broke each nut loose and retorqued them. I did them one at a time, loosen then retorque, then move to the next one. Everyone of the nuts turned a 1/4 to 1/2 a turn farther on the retorque.

Was it necessary or did I accomplish anything? Probably not, but I found it interesting. BTW These studs were used on a previous build so they had already been stretched.

 

[Duane]

True, but that's usually up around 12.5 or more with an edgy tune.

Oh I've seen guys have trouble at 11.5 cr, but he did not specify what his ratio is.

 

[MOPAROFFICIAL]

Oh I've seen guys have trouble at 11.5 cr, but he did not specify what his ratio is.

They can push gaskets at 10.1 too, just screw up the timing up bunch.

 

[siuauto]

What compression ratio ? Sbm are notorious for gasket issues at high ratios because of using only four bolts per cylinder.

It will be 11:1

 

[K.O. SWINGER]

They can push gaskets at 10.1 too, just screw up the timing up bunch.

Or crap fuel with iron heads. Many many years ago I had just got my 340 out of the motor shop and had a pretty hot tune in it. I was running low on money so I grab the gas can that was in the garage and ported into the fuel tank, about 10 miles down the road I miss the shift and started out in third gear blew out both head gaskets at the same time due to detonation I guess? and they were quality gaskets Mopar performance. I have moved to steel shim gaskets and will never look back! jmo

 

[Duane]

Or crap fuel with iron heads. Many many years ago I had just got my 340 out of the motor shop and had a pretty hot tune in it. I was running low on money so I grab the gas can that was in the garage and ported into the fuel tank, about 10 miles down the road I miss the shift and started out in third gear blew out both head gaskets at the same time due to detonation I guess? and they were quality gaskets Mopar performance. I have moved to steel shim gaskets and will never look back! jmo

I agree that a bad tune can blow the head gaskets, so can excessive overheating etc. IMHO though we are missing the point.
The op has asked when to go studs.
Before the release of the Fel pro 1008 head gasket, sbm,s even in good states of tune and proper fuel, were notorious for head gasket failure.
The root cause as mentioned in a previous post is that the sbm only uses 4 bolts per cylinder compared to say a Chev that used five.
The design of the engine has less clamping force on the heads.
Running up the ratio aggravates this.
Mopar use to recommend the Fel pro after 11:1 I believe.
The 1008 gasket was a big break through for sbm in the day.
Today we have the Cometic taken from Diesel engine technology.
The Cometic with studs greatly improved reliability with high compression ratios. The arp studs instructions call for an additional
20 ft lbs of torque to get to optimum clamp. This alone is a torque, that stock bolts will not take because of the metallurgy of the bolt materials. The op has already committed to buying some kind of aftermarket arp product. For my money I would go right to the studs, because it is a better choice for reliability. IMHO

 

[Duane]

My current engine has studs, it’s 11.2-1. The previous two were 10.8 and 11.4-1 and used ARP bolts. All three engines used Fel Pro 1008 head gaskets. IMO at my compression they’re all I need.

One thing I did on my current engine was after installing the heads I let it sit overnight. The next day I broke each nut loose and retorqued them. I did them one at a time, loosen then retorque, then move to the next one. Everyone of the nuts turned a 1/4 to 1/2 a turn farther on the retorque.

Was it necessary or did I accomplish anything? Probably not, but I found it interesting. BTW These studs were used on a previous build so they had already been stretched.

If my memory serves me, I remember that Tony aarcuda member was posting on here maybe a year or so ago that he was failing head gaskets in his 10 second car at 11:5 compression. He switched to cometics. The felpro is claimed reliable up to 12:1, but how many members are speculating there ratio. How many actually blueprinted it with Ccing and fluid and factored in the diameter of the gasket bore etc. I ordered a custom Ross piston at 12:1. Actual blueprinted
Ratio using the 1/2 inch down fill and allowing for gasket thickness and bore and Ccing one head chamber was 12.7, just sayin.

 

[justinp61]

If my memory serves me, I remember that Tony aarcuda member was posting on here maybe a year or so ago that he was failing head gaskets in his 10 second car at 11:5 compression. He switched to cometics. The felpro is claimed reliable up to 12:1, but how many members are speculating there ratio. How many actually blueprinted it with Ccing and fluid and factored in the diameter of the gasket bore etc. I ordered a custom Ross piston at 12:1. Actual blueprinted
Ratio using the 1/2 inch down fill and allowing for gasket thickness and bore and Ccing one head chamber was 12.7, just sayin.

I know a lot of guys who have ran the 1008 on pretty stout small blocks and never had a issue. How many guys actually measure everything needed to accurately figure the the compression ratio? I don't have a clue, I can only speak for my self. My small block just ran 10.008 at almost 135 mph on pump 93 and 3300 pounds. My engine is five years old, maybe I need to check if my Fel-Pro's failed?

 

[MOPAROFFICIAL]

I agree that a bad tune can blow the head gaskets, so can excessive overheating etc. IMHO though we are missing the point.
The op has asked when to go studs.
Before the release of the Fel pro 1008 head gasket, sbm,s even in good states of tune and proper fuel, were notorious for head gasket failure.
The root cause as mentioned in a previous post is that the sbm only uses 4 bolts per cylinder compared to say a Chev that used five.
The design of the engine has less clamping force on the heads.
Running up the ratio aggravates this.
Mopar use to recommend the Fel pro after 11:1 I believe.
The 1008 gasket was a big break through for sbm in the day.
Today we have the Cometic taken from Diesel engine technology.
The Cometic with studs greatly improved reliability with high compression ratios. The arp studs instructions call for an additional
20 ft lbs of torque to get to optimum clamp. This alone is a torque, that stock bolts will not take because of the metallurgy of the bolt materials. The op has already committed to buying some kind of aftermarket arp product. For my money I would go right to the studs, because it is a better choice for reliability. IMHO

I've put a few together with cometics and stock head bolts. I even spoke with cometic on the phone and they never said I couldn't use the stock head bolts..and they knew I was.
Dont get me wrong about the 4 bolts, but its played out chevy guy jab nowadays.
Better gaskets and more knowledge about where to start with tune.

He is at 11.1, then figure the camshafts role in determining the actual dynamic/effective.
I gave my cents already, I wouldn't bother with studs . Illinois has better gas than I do in California, so that should speak for itself.
If he wants bulletproof sure go studs, cometics, bottom end studs, main girdle, o ring it..the works..in fact the block could be the weak link..better sonic test every hole 6 ways to sunday..cause they're know for deep pock cavities water jacket side...then that rear lifter bore at no.7.. that thing might break, according to chevy lovers...so buy an R block now.

Joking aside. .
Do whatever you want, it's not always as complex as you might think it should be.

 

[Duane]

I know a lot of guys who have ran the 1008 on pretty stout small blocks and never had a issue. How many guys actually measure everything needed to accurately figure the the compression ratio? I don't have a clue, I can only speak for my self. My small block just ran 10.008 at almost 135 mph on pump 93 and 3300 pounds. My engine is five years old, maybe I need to check if my Fel-Pro's failed?

The felpro gasket work, never said they didn't.
You have some stout performance there. Very impressive!!

 

[siuauto]

I've put a few together with cometics and stock head bolts. I even spoke with cometic on the phone and they never said I couldn't use the stock head bolts..and they knew I was.
Dont get me wrong about the 4 bolts, but its played out chevy guy jab nowadays.
Better gaskets and more knowledge about where to start with tune.

He is at 11.1, then figure the camshafts role in determining the actual dynamic/effective.
I gave my cents already, I wouldn't bother with studs . Illinois has better gas than I do in California, so that should speak for itself.
If he wants bulletproof sure go studs, cometics, bottom end studs, main girdle, o ring it..the works..in fact the block could be the weak link..better sonic test every hole 6 ways to sunday..cause they're know for deep pock cavities water jacket side...then that rear lifter bore at no.7.. that thing might break, according to chevy lovers...so buy an R block now.

Joking aside. .
Do whatever you want, it's not always as complex as you might think it should be.

Thanks for the post, lots of good stuff here. I'm leaning toward studs. I know if I have to remove the heads it might be a pain bus as someone else mentioned, I can just remove the studs. I will be running cometic head gaskets. I have been running them on a few other engines.

Everything on this engine will be stout. I have a molner crank, molner rods with arp bolts. Race tec pistons, Cam I have not chosen but it will be a solid roller cam, Trick Flow heads, Hughes valvetrain etc..