Have you heard this, or do you know this? Just curious, as I've seen/heard of a few 0.029" head gaskets on zero-decked blocks out there.

 

Who has ever had a Impy or thinner Mr. Gasket HG cause a problem on a stock motor?

I have them with no issues.

It will make a little more power. Not worth tearing down to do, but if your there why not.

 

Thanks for the reply. I'd stick with something proven safe, and give up the 6 ft-lb tq gain on a 400HP motor but that's just me. (1.5% gain)

Dan

 

what's something proven safe?

 

Exactley, raise your hand if you have a problem related to any of the gaskets listed here on a stock motor??

More internet wisdom spreading rapidly.

 

Stock deck height, pistons and combustion chambers you're not going to be running any risk by swapping out, the time it gets risky is if you've changed any of those factors and either the compressionl'l be too high or the pistons will come closer than .040 to the heads, stock pistons will come ~ .050 to the heads which is quite safe.

 

I blew a fel-pro .039" gasket and now I'm running a .027" cometic with no issues...

 

The guy that I had install a cam and top end package on my car like 8 years ago used them. I got at least 30k on the engine before an unrelated problem caused the need for a rebuild. So, yeah, they worked. But I was was not interested in using them again and did not on future mods and head changes.

Give GM engineers some credit for knowing the differences between iron and alum heads and learning over the years that a different gasket is needed for each.

I am an old school guy and as I understand the first year for alum heads on a BBC Vette which was in 1967, they had some gasket failure problems later corrected with a better, alum head only gasket. BTW, I had a 67 427 435HP vette with iron heads. I acquired some used L-88 alum heads but never used them...but that is another story.

As has been mention many time, why take the chance with a gasket designed for an iron head?

 

Everyone can make their own choice. I have no issues with guys using the Impy or Mr. Gasket head gaskets. For the minimal gain, I would prefer to have just that tad extra clearance if my valve bounces or valve float sets in because I over rev...

Dan

 

Becuse you had them for 8 years and never had a problem. Most performance motors don't go that far between tear down so why not.

Plenty of people have crapped out the stock gaskets so I guess the thinner Impy or Mr. Gasket replacements are better than stock.

We are not talking BBC's or the 1960's. We are talking LT1's.

My question still stands, any one have a first hand problem with the thinner HG on a stock LT1??

 

You realize that cam choice is going to have more of an influence on PTV clearance than shaving .020-.025" off a head gasket right??

 

I measured mine with the Mr. Gasket HG and couldn't touch anything with the valve with the piston at TDC and this was with +.050 locks.

The retainer will hit the top of the guide before you get piston.

 

Yes, true, true.

Dan

 

Just my two cents here:...I've NEVER once heard of an issue running the Impala gaskets.........Im currently running them with pretty close to 700 crank HP on the bottle, and they are holding up perfect........Having a head gasket that came from the factory on an Iron headed engine usually just gives you a harder fire ring material in the gasket...which can brinel the soft aluminum heads surface a bit more(which is the reason they list them for Iron heads)......But the fact is, they don't brinel aluminum heads very much after their use, and a normal skim cut head surfacing, which you would do anyway "anytime" heads are going on, is "plenty" to remove the harder fire ring indentations............EVERY little bit here and there helps, "especially" concerning compression.....which is one of the 3 most important and drastic performance aspects(Heads, Cam & Compression).........besides, LT1's have a TON of valve to piston clearance from the factory.....going 20 thousanths thinner with a head gasket, still puts most people NO WHERE near of things getting close.......Like mentioned this is MUCH more a product of cam LSA...........Joe