I have a 528" stroker for street use. Between decking the block to get the decks straight and line honing the pistons are now out of the hole .016". The 528" pistons have a very short skirt so piston rock also plays a part here. With the thickest Felpro head gasket (.052") I'm left with .036" quench. I think this is too close for comfort for a street motor. Using Cometic MLS gaskets isn't an option because the block (and probably the heads as well) don't have the correct RA finish. I contacted Cometic and they can make a standard style custom thickness gasket. Looking for some thoughts here. What's a "safe" quench dimension for a street motor?

I have and do currently run .030 on a SB without blinking an eye, I don't think you have anything to worry about as far as piston to head.

Racers have successfully used Cometic gaskets with RA all over the map and copper coat
For quite some time now. I realize it's not perfect and it's not recommended by the manufacturer, but sometimes
You have to make do....

You could probably shave a little off the tops of the pistons.

On my 512 low deck, I used the .051 Cometic with piston .016 out of the hole.

The motor is fully assembled. Thicker custom head gaskets are the easy answer - if deemed necessary.

just ring Cometic and order the thickness you need .
I have 0.040gasket for 0.040-0.042 quench in my 505 , I think i ran 0.037-.0.038 quench on my old 505

Tex

0.036" on a street engine should be fine. What is the peak RPM the engine see, 6,000 RPM?

Does the person who put the motor together with the pistons sticking out have any ideas on how to solve the problem?

.036 should be fine.. dont worry about the RA just use copper coat in it

Go through and check all eight pistons at TDC and use a thin bladed screw driver between the tops of the pistons on the cam side and motor mount side to rock the pistons as far over as you can get them both ways and measure the piston height above the decks on the outer edges and go from there
If you get .020 or less above the decks I would run it If it is above .022 or more get a thicker head gasket

Whose piston and whose rod? .035 is ok for a street engine but barely. RPMs will also come into play there. Hate to mention it now but you might want to check the Piston to valve with the pistons rocking around like you noted.
Todd

No he doesn't. It pisses me off that he didn't measure the deck heights and do some basic math before machining things. At some point he could have said it was going to be tight and I would have found another block.

Been there, done that. Plenty of ways to skin a cat...one of them being (what I would do FWIW) first measure p-2-v. Provided there is adequate clearance remove pistons and chuck them up in a lathe with a thin aluminum band around the ring pack area (round grab) and cut .005" or so off the top, reassemble.

How close is the top ring to the deck? Is there a bevel at the top of the bore?

The difference between where the piston is supposed to sit at TDC (-.009) and where it is (+.016) is not enough to matter about the ring or bevel.

Big bore, short piston........ I’d be shooting for around .050 piston to head clearance.

Yeah that is a bummer. Typically I'd get a call from the engine builder saying "um, your block is a little short. What should we do". I'd be pissed if I showed up and the pistons were sticking out of the holes since now you have limited options.

I think even with piston rock you will have 0.030" min clearance. That should be OK with steel rods and 6,000 RPM.

I know 0.020" is too tight on a 440, but the engine ran for quite some time until it was over-reved.

KInd of had the same scenario with the R1 block in my car. When we put it together the pistons were out of the hole, machine shop forgot to say that the block needed a little more taken off to square it up. We were able to fix the issue with .056 cometic gaskets. I will say the cometic have worked great and I will re use them after this top end refresh.