MLS Head Gaskets + 400 SBC = ??

I just bought a set of Fel-Pro MLS h.g.'s for my 406, and noticed that they don't have the steam holes. Can I drill 'em, or will it ruin the gaskets?

 

Check the bore size. If they don't have steam holes, make certian they're big enough. It's easy to do and it's easier to return them before they're drilled!

 

Bore size is 4.200, my cylinders are 4.155. Not a problem there, I just hate to put a drill to the $85 gasket without being sure!

 

Street motor? If its race then dill and tap the steam holes for plugs. The original GM block have a habit of cracking from the steam hole to the head bolt hole. Race gaskets don't have the steam hole.
I don't know if i would use MLS for the street if it is street.
I like the nova in your avatar, stick? The steam holes in the 400 in my avatar for sure are plugged (67 nova)

 

Cometic shows different p/n for 'with' or 'without' steam holes.
http://www.cometic.com/domesticauto.aspx

 

It's a street motor...I've got 5 summers on it. Changed to the MLS gasket (.061") to try and lower the compression a bit so I don't have to shut it off in Drive anymore. I'd like to just drill the gaskets but I've never used these MLS.
The Nova is my buddy Jim's, it's a 283 Jerico.

 

What will your quench dimension be with the thick gaskets? You may be able to get the combustion chamber cleaned up by running an APO vapor injector. Worked for me on a 300 horse 350 in my '70 Monte Carlo, on regular. Keeping the quench tight is paramount for running any kind of compression in a small-block.

 

Cometics are a ***** to drill.I add two water transfer holes on a donovan big block and had to drill them out. Finally, got Cometic to pattern the holes and they do it with a part number. I would return them and get ones with the holes in. If you have to drill, I get a better result if you take them apart and drill one at a time, rivet back together. Pain in the ****.

 

As stated, get the correct gaskets with the steam holes already drilled. And as also stated, you just added enough to your quench dimension to create the perfect detonation bomb.

 

Well guys, sorry for wasting your time...after I looked closer at the gaskets, I see that the holes are actually there. As for the quench, I gave that a lot of thought before I bought the gaskets...here's my story, I'd like to have your feedback: the heads are 041 castings that I've been running since '97...64cc, with 2.02 / 1.60 valves. They've been "cleaned up" (surfaced) maybe 3 times since I've owned 'em, I'm guessing a total of .030-.045"...they were on a 4.060 bore 327 until 2005, when I built the current 400 which is 4.155. I'm using a Sealed Power dished piston, H615P, .135 dish. I've driven the car the past several years...even drove it to Austin for the Roundup in '07 from Omaha...and have put up with high compression symptoms the whole time: had to pull the total timing back to 32 deg. to keep it from pinging, always had to shut it off in gear to keep it from dieseling, etc. Soooo, last week I decided to try thicker head gaskets. I thought about the quench, but looking at the top of that piston, I really doubt you could achieve quench with it. Am I all screwed up? I do realize that the right way would be to switch to some new heads with 72cc chambers, but the $$ just aren't available. Here's a pic of my slugs:

 

There is some quench there (not ideal, but better than a full dog dish).

Is that $85 / gasket or for both (I prefer the Cometic brand, you say FelPro and I've never priced any of their MLS stuff, so ).

If it's per each, the old Edelbrock water injection seutps usually show up on that auction site for cheap.

I've heard of people doing more or less the same thing with a needle valve inline to a water source hooked to a vac*** tap at the carb (IIRC JC whitney used to sell one like that).

Not the end all be all for sure, but might be worth a shot if you don't have your engine apart yet.

Have you tried different spark plugs (colder heat range, non projector tip, etc)?

I expect you have but I have to ask.

 

Yeah, they're $85 each...the average Cometic looks to be in the $90s each. I went colder on the plugs awhile back with no results. The water injection may be worth looking into...

 

The edelbrock setup used a washer pump and discharged over the primarys IIRC, it included a "brain box" that would not let the pump run (sipposedly) when the engine was off so you wouldn't fill the engine up with water. I don't really see why a simple hobbes switch wouldn't do the same thing.

I guess the hard part (if you were building it yourself) would be to get a nozzle setup that was robust enough not to break off and go down the carb and get decent atomisation at the lower pressure (the newer stuff runs a more expensive, much higher pressure pump).