302 Valve Cover Questions?????

I had a little bit of a clearance problem with throttle linkage when I put Ford motorsport valve covers on. I added a 3/8" phenolic spacer to gain enough space.
 
The valve cover surface of the TW heads is taller actually raised to help with RR clearance (.300" if I remember).

Since there are a ton of possible combinations that you could use it may be a good idea to measure things out before you buy something. Or just buy it and see if it fits.