one that works with 2000 year model heads / block. I gurrently have the graphite gaskets but I know the MLS are slightly thicker. I've searched but found varying information about whether the newer (thicker) gaskets work with older blocks. Is anyone running newer gaskets on older blocks / heads or does anyone know what will work?

 

Also, if Fel-Pro has a head gasket thicker than any of GM's I'd be interested in those, too.

 

What do you need a thicker gasket for? Details please.

 

I have a 2000 FRC 346 with TEA 5.3L heads that have ostensibly been milled 0.020"
I'm getting some ping at high RPM and in 6th gear under load, even with 95+ octane with xylene added to pump fuel.

I'm planning on programming some of the timing out with HP Tuners to see if that helps, but I believe that either the heads were milled more than 0.020" or where they stand they're causing too much compression. Looking at the info here it would appear I'm running about 11.7:1 compression which shouldn't be terrible on 93 or 95 octane. Still, I'm getting ping and I want it to go away.

My graphite gaskets, I believe, are 0.052" thickness when compressed and I'm thinking the MLS gaskets at 0.060" would be a sufficient improvement if they happen to work on my block / heads. The block is a 2000 casting. So are the 4.8L / 5.3L heads.

if you have any ideas, let me know.

 

Get it tuned by someone who is a pro at it. .020" shouldn't be a problem. I think if you remove some timing it will work.

 

.020" on top of truck heads (designed for dished pistons) may be a little excessive. Further, I can't verify that they were actually milled only twenty thou, but the lash on 7.400" pushrods seem to verify that it's at least close.

 

Your cam can determine your DCR, too. That can play a role in detonation.

A good tune can remedy all of that. And much easier than swapping headgaskets out.

This is why all things, heads, etc should be measured on pre-assembly to be sure you hit your desired SCR, etc.

 

At what RPM is this?

6th gear and high RPM equates to 180 MPH+ speeds in my brain. Where are you running this speed? lol

 

good point, cannibal. Don't really know how to calc the dynamic compression ratio but the cam is a single pattern 224° on a 115° LSA so I imagine my dcr to be on the high side relative to the scr. what do you think?

 

To be clear, those are two separate conditions. High rpm in third / fourth OR at low rpm [<1700] in sixth gear.

 

Ah, makes more sense now.

 

a thicker gasket will make your quench higher and in turn will cause you to ping more then the .052 gasket.

using stock perameters and 5.3 heads milled .020 i come up with 11.57 SCR and a .044 qench. with the .060 gasket it comes out to 11.33 SCR and a .052 quench.

just guestimating on the DCR i come up with ~8.6

 

thx for the response. can you please explain how that works or direct me to somewhere I can further understand?