I'd be more concerned about it blocking bottom end oiling holes.

cant rely on the filter to clean out any silicon before it gets lifted to head? or would the pressure push the silicon through the filter?

the point that it can block up oil galleries is fair to say, altho every honda and alot of manufacturers actually use and reccomend these sealants

Silicon is no good, can block oil passages.

I just use aluminium spray paint on head gaskets.

Use this on everything else.

permatex ultra copper, we use a honda genuine sealant at work.

permatex no.3 will not seal a sump it is generally used on thermostat (coolant) gaskets it does not actually set and you will never get it to 3.5mm

all loctite products are great

i would use a loctiite silicone product

i have used the loctite copper silicone on the exhaust housing flanges of my turbos without any leakage. it is awesome stuff, better than any gasket

lagwagon also gave it a shot on his sr20det turbo manifold flange and he told me it lasted longer than any gasket he has had in there, not sure how long he had it in there in the end but knowing him he has changed the turbo 20 times by now

i also used the typical blue or red loctite silicon on my sump with no trouble

So the options are:

Permatex Ultra Black Maximum Oil Resistance RTV Silicone Gasket Maker
Permatex
Suggested Applications: Valve covers, oil pans, intake manifold end seals, timing covers, transmission pans

Loctite
Loctite

Permatex #3 - got some of that - I've used in on the two rubber seals on the front and back of the sump, I didn't think it looked solid enough to form a gasket between the sump and the block though.

So just to confirm that is Permatex #3 by itself with no gasket between block and sump?

i treid making a serious face once... ended up making a serious mess in my pants

stay away from silicon branded stuff. i couldnt even get their gasket maker to make a water tight gasket on the thermostat housing, then used some other stuff and never leaked a drop.
cant read the brand as its coverd in gunk from squeezing too much out,

PERMATEX #3 AVIATION I have used nothing else in 35yrs of working on machines. I will never submit to using any silicone products. Seen that crap block oil galleries and blow up bits. Serious Face!!