Max lift on stock guides and seals?

moper said
No - I meant issues with coil bind as opposed to retainer to guide - sorry if I confused.

I think I understand what you are saying, regarding coil bind. Getting rid of coil bind requires changing the install height on the spring to be taller, somehow, so you have to cut the floor of the spring seat or change retainers that have a taller height. I was thinking that maybe you were talking about coil against the guide or seal clearance, on the inside of the coil, I got it now, though.

moper said
You might have an issue with the 360s exhaust valves - they may have the lock groove lower than the intakes if the engine had the rotators on the exh valves. I know the 901-16s on my truck have a slightly heavier seat presssure than the intakes becasue of that. I removed the rotators but the lower groove remains. It's no issue - the cam is small - but it's something to watch for if you're not replacing the valves.

I think any cylinder head with rotater retainers have a different, lower groove in the valve stem. The 302's that I went through had rotaters on the exhaust and the valve springs are significantly shorter on those. That brings up the possability that perhaps Hughes is giving a .450" measurement to take these retainers into consideration.

I did replace the valves in them as well as the retainers and locks. I'm still waiting on replacement springs from Hughes, so I haven't put anything together, yet, before measuring. I'll just double check the retainer to guide height and installed height of the spring against suggested install height.