408 build question????

M

mx106

New Member

May 16, 2005

10

0

0

upstate ny

Mar 4, 2009

#1

• Mar 4, 2009

• #1

hey guys, building a 408 and have z304 motorsport heads. couple questions: should i use head studs on this motor? what would you guys recommend for headgaskets (the heads are not oringed, and the motor is 9.3:1 compression, in which i plan on turbocharging with under 10lbs? any help would be great

 

95Vert383AOD

15 Year Member

Jun 10, 2008

1,133

34

69

New Bedford, MA

Mar 4, 2009

#2

• Mar 4, 2009

• #2

Go ARP studs...Not sure on the head gaskets. Mine are O-Ringed. The fact that the head bolts are thicker on the 351 than those found on the 302 means the head gaskets are less likely to shift. Studs tend to have fine threads where the Nut attaches allowing for a much more accurate torque reading. The bolts come in 2 flavors. Hex and 12 Point. While youre at it get a nice set of ARP intake manifold studs too.

 

Bullitt347

I have been doing it wrong this whole time

15 Year Member

Mar 23, 2007

4,061

3,132

204

Middle of Maine

Mar 4, 2009

#3

• Mar 4, 2009

• #3

Use Cometic Head gaskets, while spendy, they work great and are re-usable. They are a multi-layer steel shim design. Make sure the deck is flat and the heads are flat. Use head studs.

 

Rick 91GT

Mustang Master

Nov 29, 1999

9,692

95

99

PA

Mar 5, 2009

#4

• Mar 5, 2009

• #4

If you want a MLS style headgasket go with the Fel-Pro's PT#1133 is what you will need. These have a tendency not to leak through the layers like the Cometics, which I, like others find you have to coat them with a sealer.

If you want a headgasket that will be more like a fuse use a Fel-Pro 1011-1...

I'd also suggest studs....

 

S

Stopsign32v

Member

May 18, 2008

394

0

16

Gville, SC

Mar 5, 2009

#5

• Mar 5, 2009

• #5

Studs are a must with boost.

I hate Cometic gaskets. I coated mine and still could not get them to seal. Unless you plan to boost alot I would stay away from MLS headgaskets. They are a bitch to get to seal. Some have luck, some dont.

 

Bullitt347

I have been doing it wrong this whole time

15 Year Member

Mar 23, 2007

4,061

3,132

204

Middle of Maine

Mar 5, 2009

#6

• Mar 5, 2009

• #6

Cometic is the gasket the factory uses on all of the 4.6/5.4/6.8 engines. I have used them with great success without a single leak. Even on a 13.5:1 compression 347 using a 250 h.p. shot of nitrous and spinning it past 8,000 rpm's I never had a head gasket issue. Have used them on a 331 cid supercharged engine running 18 psi for 4 years without 1 head gasket issue. So I guess it comes down to how the engine is put together and not the gasket itself. And in all cases I never used a sealer of any kind on the gasket, just installed them dry. That is why I recommend them, but that is just me I guess....

 

Rick 91GT

Mustang Master

Nov 29, 1999

9,692

95

99

PA

Mar 6, 2009

#7

• Mar 6, 2009

• #7

The Fel-Pro MLS come with a slight tacky coating on them now which I find helps, I have yet to have one leak between the layers. A few years back Sam Vincent NMRA Outlaw N2O racer told me to use the Chrysler gasket spray with the Cometics and he had never had a leak, I found that to be 100% true and very effective.

Don't be afraid of the MLS gasket, they are perfect for high cylinder pressure combo's just make sure the heads and block have the proper finish. The MLS gaskets will also require the retorque of the studs after it gets a heat cycle or two.