Valve covers on my 427
 

I've rebuilt my 427 that I've had for 30 years, now I'm not able to install the valve covers. The valve covers are rubbing on the rocker arms by the push rod ends. When I had the engine down, I replaced the valves and push rods. I haven't checked back with the parts supplier yet, but I'm not sure that valves or push rods would cause that. I got two new sets of chrome valve covers and one set of aluminum ones, none of them will clear.... ???? I do have the original chrome ones, and they seem to clear the rocker arms ok. I haven't found anyone else that has this problem. I thought that I'd throw it out there and ask before I made myself go crazy. Thanks

I believe if you check the physical shape of aftermarket to OE cover, you might find the aftermarket is slanted to the middle of the head, plus the alum wall is thicker as alum covers have the same outside dimensions as OE.

You might Dremel tool grind clearance patches on covers because you don't want to mess with the rocker arm - keep its strength.
Maybe add a second cover gasket?

No, pushrods do not change rocker arm geometry.

It's surprising that no one else has experienced this. I have friends with big blocks, and on one else has even heard of this. Camaro Central has sent me two sets, and said that they haven't heard of this either, that's why I thought that maybe the aluminum might fit better. My friend has the same set on his 396 with no problem. I don't think that I can remove enough metal to achieve the clearance that I need. I may need to have my original valve covers re-chromed, but that shouldn't be necessary

what is the depth of the valve cover?
are the rockers stock?

The engine is basically stock, the only modification was a mild cam and aluminum intake. I borrowed a set of factory 502 valve covers, they fit ok. I'm not sure what to think, it doesn't make sense.

compare old and new pushrod lengths and then do a dye check on where your rockers are riding on the valve tips.

The pushrods all seem to be correct, but I removed the rocker arms and lined them up against a straight edge, and there is as much as 1/4" difference in length. I put 4 of the shortest ones on one side on the intake valves and that fixed that side. Now I have to decide if I'm going to buy a new set of originals, buy a set of aftermarket, or just try to find four more short ones. The intake and the exhaust are suppose to be the same, and I don't feel good trying to grind the ends to make them fit.

I know its not the same deal, but this should help you

most of the guys in the LS world with aftermarket rockers can't use a stock valve cover because it hits in the same spot you're talking about, a lot of the manufacturers are starting to make valve covers like the photo I've attached, you can see they punch out the top of the valve cover to make more room, maybe something to consider for you as well, I know I had to

didn't you have a picture of the rockers, weren't they the roller tip ball mount style rockers? I have been running those rockers under stock height covers on my SS454 Monte for over 25 years now.

Mr. Gasket makes a thick cork gasket that may help with the clearance.

If there's a 1/4" variance in the length of the rocker arms, I'd start from scratch and get a complete new set and measure them. Are they roller rockers, and if so, what ratio? BTW, I'm running Eddies Motorsports cast polished aluminum tall valve covers. The outside edges are slanted to the center. My engine specs are in signature.