The manufacturer lists the compressed thickness as .039" but I found a thread on Moparts that says the compressed thickness of the Fel Pro 8519PT can be anywhere from .041" to .044".

I'm doing a head swap and measured one of my cylinders' pistons as .003" below deck so while I'm at it I have a chance to get the quench distance pretty ideal if I can pick out the right gasket.

This is on a .040" over 440 with 84cc E Street heads. Are there other gaskets that would be a good choice? I read on here that the .039" fel Pro 1009s might not work because of hanging into the bore and the fire ring brinneling the aluminum heads. Thanks!

if you want the motor to be exactly as you want it to have on the quench distance call Cometic gasket CO.and have them make you the gaskets for your bore, deck and head CC to get it like you want it

If the manufacturer says it's .039" they probably know. If they are wrong and it's .002" thicker....I don't think the sky will come falling down.

I agree.
I used those same gaskets on my 440. I was able to get .042 worth of feeler gauges between the head and block with that gasket torqued to spec. Close enough for me.

Could be a couple thou less too. The only way to know for sure is to install one, remove it and mic it.

My builder lost a hydroplane championship over one that crushed to less than spec. The rules spec'd a minimum .039 piston to head, on tear down the gasket measured .037" on a zero deck.

Kevin

No I don't think so either. Just trying to strike a balance between taking advantage of quench with a number in the .040" to .050" range and not worrying about having my heavy 2355 "6 pack" pistons hit my heads. So far I've taken some preliminary measurements and gotten .006" below deck on cylinder 1 and .003" below deck on cylinder 6. So if the Fel Pro 8519s really measure between .041" to .044" compressed it would work out well for what I'm doing.

Make sure and rock all the pistons over in the bores and measure the pistons at the edge the outside edges in the bores closest to the cam and motor mounts
I use a thin bladed screwdriver wedge between the top of the pistons and bores gently to rock the piston against the other side of the cylinders and then measure the edge of the piston to get it as close as it will be when running on the firing stroke

Thanks Cab, yeah I already noticed that the number 6 cylinder was different from the cam side to the engine mount side without even rocking it.

I can't imagine what machining is involved to start with factory crank, rods, and block and get all 8 cylinders on both sides to come out to exactly zero deck. Maybe someone here has done it?

I ran into that with some SB felpros, they didn't compress to what was stated & my torque was correct. Maybe they need retorquing after setting overnight or retorqued after breakin, not sure just going by what the felpro man & dave hughes have mentioned in conversations. I have a new 408 & I want dead on 040" quench so I did what Cab mentioned & went with some .040 compressed Cometics & I will be trusting that they will go to what they say they will. EDIT some people have mentioned spraying the individual layers with "high tack" ??? Not sure if needed or not & how that would affect thickness, maybe just KISS & drill out the rivets & call em good.

As long as the block and head surfaces are 50RA or smoother I wouldn't put anything on any MLS Cometics head gaskets
no matter what others have suggested on here and other sites, I've used and reused many sets so far without any failures installing them dry

I will follow that advise, Thanks Cab