Phil99vette

iTrader: (11)

Man, you ask 10 people on which head gasket setup is the best and you get 15 different answers. Here's what I using

Iron GMPP LSX
Converted from 3/8" => 1/2"(main holes) and 8mm => 3/8"(5th and 6th holes)
ETP LS7 heads with their thick deck design
ARP studs
Bore 4.165

I really want to run an O-ring setup with a reciever groove but I've heard probably 50/50 on their performance. Because of the bore spacing and bore size I won't be able to run SS wire around each individual cylinder. I have to use a figure 8 pattern which leads me to problem 2 more later.

Alot of my import buddies that are making comparable power(200-250 per cylinder) are running O-rings in their block but no reciever groove in the head. A handful of them started with reciever grooves but removed them because they said that the receiver groove made them more prone to blowing head gaskets. A o-ring'd block would be a piece of cake but I'm also trying to weigh the durability and long term goals of the project. I've heard of a couple of people using an o-ring'd block and an MLS gasket.

Some of the local guys that are running the 10.5" tire class swear by the MLS gasket without an o-ring. Can't see how that would work correctly though.

qqwqeqwrqwqtq

I'm building a setup with about the same hardware as you, except 4.125 bore. I'm going to see how far I can take it with Cometic MLS and no o-ring.

We've built a few setups with 1,150+rwhp using stock sized ARP studs and GM MLS gaskets and 6.0 iron block.

I think the integrity of the LSX block will go a long way in gasket sealing, not to mention the additional (and in this case oversized) fasteners.

ILLINTENT

iTrader: (4)

In relationship to this discussion, how critical is the head-deck thickness. I am using an iron 6.0 block as well with a 4.030 bore, and had considered using the stock MLS gaskets and stock diameter studs. (ARP)

I am also trying to use a stock head casting, which I understand to have thinner deck sealing surfaces... do I need to go to an aftermarket head for sealing purposes???

Like the thread starter, I am a little hesitant on the o-ring routine. Coming from the small block ford world, I am familiar with the 4 bolt per cylinder sealing issues.

TT632

iTrader: (3)

Switched from copper/o-ringed block to cometic MLS a few years ago. No issues to date. In the copper o-ringed days, seemed to have water leakage issues from time to time.

LS1curious

Hands down the best gasket out there is the MLS Fel-Pro Head Gasket. It actually seems to work on SBf,buick,SBC etc engine very well. It doesn;t leak like cometics and has a much better design overall. It also allows for some head squirm. I think fel-pro may already have a 6 bolts gasket for that block to.

TT632

iTrader: (3)

Are these advertised as a performance gasket? I would like to try them, I just haven't talked to anyone that has had high power levels (lets say over 1000 RWHP) and used these gaskets. Ive also noticed the price is better than the Cometics also.

Phil99vette

iTrader: (11)

I wonder if they offer custom gaskets.
Phil

Phil99vette

iTrader: (11)

Fel pro makes all of the new gaskets for the LSx block. 1162 L & R is the 4.175 bore.
Phil

qqwqeqwrqwqtq

Where did you find that part #?

Phil99vette

iTrader: (11)

I called Fel-Pro but I'm starting to think its the wrong number. I'm going to call them tomorrow. The rep said it was the 6 bolt per cylinder with 4.175 bore.
Phil

edcmat-l1

iTrader: (10)

http://www.scegaskets.com/products/ics.html
Check these out Phil.
I'm not crazy about MLS gaskets in general (probably the only one) I know they work ,and all the OEMs are using em, but....
These offer the the best of both worlds. solid copper design, with integrated fire ring that actually should help seal under pressure.
BTW, the 346 is running GREAT!!! We'll put it on the dyno tomorrow.
Gonna drive it today.

Phil99vette

iTrader: (11)

Sounds good. Kurt said that those gaskets let go about 1500hp. I'm really leaning towards a SS o-ring in the block stickin out .008 with MLS gaskets. I know people that make 250-300 per cylinder with this setup.
Phil

qqwqeqwrqwqtq

We pushed those gaskets out with only 14psi/850rwhp on our shop car. Made no other changes other than installing GM MLS and have had no other issues.

This was a few months ago. At the time SCE told us they were going to stop selling the LS1 version of the ICS gasket as they were having so many problems with them. (whether or not that actually happened I don't know).

Phil99vette

iTrader: (11)

Yeah, kurt said that they gave with the bigger head studs @ high 1400-1500hp. I'm really crossing my fingers that with:
1) 6 head studs - 4 - 1/2" && 2 - 3/8"
- standard 8740 material, L19 would have too much clamping force
2) .800 thick deck on the ET heads
3) .041 SS O-ring wire in the block hangin out .008
4) Fel Pro 6 bolt MLS gaskets
5) Iron LSx block

I can keep the heads down and make in the neighborhood of 225-275 hp(1800-2200hp) per cylinder when everything is all said and done.

edcmat-l1

iTrader: (10)

Very interesting. We were gonna try them in a SC mopar we're having trouble keeping head gaskets in. Maybe not now.

qqwqeqwrqwqtq

Hmm, I'm no expert on o-ringing but I would tend to think a SS o-ring (even protruding only .008) would hold the head up off of an MLS gasket.

helicoil

iTrader: (104)

Felpro should have some pieces out for the LSx and Warhawk 6-bolt block in the next couple of weeks.

Currently, the R07 head gaskets are out (Nascar) block and are a P/N 26452.

The LSx stuff will be:
P/N 26473 4.200" bore (first to arrive)
P/N 26472 4.100" bore
P/N 26474 4.270" bore

These will also fit the Warhawk.

P/N 1185 has been designed for the Warhawk specifically and should be out by the end of July.

All are MLS.
Initial testing on the LSx block has shown HP potential to be in the 1800HP w/o problems with 6 bolt heads and boost.

LS1curious

I have no idea. But if they will hold on in a SBF making around 1000fwhp at 22 psi of boost and 10.5:1 compression they should hold up in anything. This was after the cometic was puking at the same power level.

Make a note of this however. If you use a MLS Felpro the Head and block surfaces need very fine finish roughness. Like 10-12 RA no rougher. If the material doesn't look like glass after milling they will not seal correctly.

I would not recomend O-ringing either the block of the head.

Phil99vette

iTrader: (11)

I'm with ya but I was given the same info by 6 people from different shops. One guy has a ~1500hp 4 banger. They all said that you use .008, .011+ would cause water to leaked and .004 and below would not seal as well as the .008.

helicoil

iTrader: (104)

An Ra of 30 or less is sufficient for a Felpro MLS. However 10-12 is O.K. too. Must rotary broaches with CBN or PCD tooling will struggle to get anything better than 10.
For reference glass has about an Ra of 4-6. And early LS1 blocks have an Ra around 35-50 and people have had success converting the stock graphite to MLS.