Looking to see what sufficient valve cover clearance is. I have 3/8 spacers and gaskets for poly lock clearance. Looks like about 5/16 to 3/8 clearance.
is this enough with engine torquing?

 

I can't say what is "enough" but I have a similar setup with allot more space than you have. I doubled up on the thick valve cover gaskets and used the poly locks for my roller rockers and have more spacing as you will see in the pic. I can say that my cam is pretty radical and I'm pretty sure my engine would bump that booster in my car. The engine moves around a bit. Also...getting the valve covers off for any type of issue or inspection might be a fun project.


If you zoom in...the booster to valve cover clearance is evident.

 

I doubt the spacers are necessary with M/T valve covers. Spacers help with stock valve covers with the stock oil baffle.

 

As long as you can get the VC's on and off your good.

 

I have the MT valve covers (w/o spacers) running full roller rockers from Howards Cams, valve lift is .557/.541; I have no clearance issues with the polylocks or the rocker arms.

 

Well guess I have a few choices. I’d like to use the MT valve covers and 11 inch booster. I could try and find stock covers? Will my 350 ones work were they the same ?
maybe modify the fins on MT covers by booster and repaint?

 

I'm wondering what's different about your setup vice mine as noted? I have the same M/T valve covers with roller rockers and the poly locks. I also have the 11" vacuum booster and still have 1" or more of clearance. Is the limited clearance caused by the spacer you have installed?

 

Could be which double gaskets did you use? Did you silicone them together or how did you seal them ?

 

Yes I used the thick 1/4" cork Fel Pro gaskets and then very lightly siliconed them together. It would see like your setup should be much close to mine for the booster spacing minus the spacer block you installed.

 

Could be. Just measured the double gaskets I had before spacers. They are 3/8 thick together. They worked just leaked .
the spacers are 3/8. Then the gasket which is 3/16.
so if I return to dual gaskets. I will have .56 space. Maybe that will be enough