GM and their legendary ***** changes sizes once removed has reared it's ugly head. I've had proform center bolt valve covers for two seasons now with no issues. I had them off to do a valve adjustment and the driver's side #1 cylinder rockers are tapping the cover. Makes no sense. I've shifted them, tried everything and if the bolts are just barely tight the tapping stops. If I torque them down there's contact. I don't get it but whatever. Maybe I bent them a bit, I have no idea. Regardless, is there a thicker one available? Mine are the blue felpro rubber ones.

How about using 2 of them?

Yes I've done it before with other VCs.

Was thinking of that with those same blue ones. You don't get leaks from in between or are you siliconning them together? There's no pressure so I guess they likely won't leak

Fel-pro makes an ultra premium laminated steel and cork one. IDK if it is any thicker but it is more expensive than the blue ones.

I had some Vette aluminum VCs (perimeter-bolt) that needed that to sit clear of Loly-Locks on top of longer valves and longer push rods. I used the SOOOOOOOPER THICKKKKKKK Victor-Reiz ones for awhile butt it just didn't quite get the job done. 2 of the Moroso blue ones though, Somewhat like you described; a steel core encased in blue goo.

I used gorilla snot, putting it on between the VC and the 1st gasket and between the 2 gaskets. In both places I put it on both their surfaces and let it set up for a half hour or so before assembly. Then used grease between the 2nd gasket and the heads.

I just installed these with proform covers on my 350TPI and they are indeed significantly thicker.

The Fel-Pro CORK-LAM valve cover gaskets are .250 thick and the Fel-pro blue rubber one are .181

Fel-Pro Performance CorkLam Valve Cover Gaskets - 1648 - Summit Racing

Thanks for the info. So two blues are just under 3/8 of an inch. I already have those so I'll silicone two together and see how she goes.

Seems to have done the trick. I siliconed two Felpro VS50088R blue gaskets together and I now have the clearance. No idea what the hell happened that I needed the two, but nonetheless they are working. Just needed to be careful on centering the cover because with them being raised a bit they no longer self locate on the head.