Understandable, Ray. I know you know more than probably anyone else here about this motor........but.
You have got to be kidding me that there is only .010 right now between my valves and the pistons. HO lift at the valve is .510, and you are telling me that with a little extra heat (expansion) and a quick out of water over-rev, the pistons are gonna hit? C'mon. GM has never put out a motor with that tight of clearances, even back when they had .600 lift cams in the '70s.
I am sold on your kit, ok? There are just some of us that don't mind tinkering a little until we get there. We have been through this before. If you want us to use your rockers instead of Comp Cams or another, fine.
For the other comment about stock covers, besides the slightly different bolt pattern, there is the stock coils to be mounted. I know that Eddie and I think Rex (at least) are working on new covers with a coil bracket for under the exhaust.
Ray, I know there are spacers made, and maybe they are mandatory, but I have a hard time believing that GM has changed the spacing between the valves/rockers and covers from previous big blocks. I know of at least two 454s that are running either Stainless, like yours (or whoever's you use) and Aluminum under stock covers. The alum are not 1.8s, but I know the Stainless ones are. I have see the 1.8 motor with the stock covers on, and running. Is it really that different from a standard Gen V-VI head?
Additionally, you are saying you have moved the valve up and away from the pistons for you to be able to run 1.8 rockers or your larger cams, but the valves are still not hitting the valve covers? I don't get it! Did you space the valves away from the pistons? or the covers? I don't see how it could be both, unless you layed them sideways????