Vizard says a valve is geometrically de shrouded when the clearance between the valve and the wall is .20D of the valve at .250 lift.
The illustration in DV’s book shows a combustion chamber wall that angles away from the valve head as the valve is opened. Hence the comment on the .250 lift.

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Doo Ron Ron and the Duke of Earl are friends of mine.....
https://www.youtube.com/watch?v=uX8Nj8ABEI8

Does that mean 20% of the diameter of the valve?? If so all Slant 6 valves are probably shrouded

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2 Mopars come with Spark plug tubes. One is a world class, racing machine. The other is a 426 CI. boat anchor!

12.70 @ 104.6

Yes and Yes

_________________
Doo Ron Ron and the Duke of Earl are friends of mine.....
https://www.youtube.com/watch?v=uX8Nj8ABEI8

Finally back on this one. The cylinder head has been ported and gasket matched, as has the intake. The exhaust manifold did not need any gasket matching.
Then I dropped the head off at the machine shop for a valve job and cutting the valve guides down for more clearance and positive type valve stem seals. Still waiting on that.

But then it turns out some of the items I've ordered aren't quite right. The freeze plug set didn't include the cam plug. Is there supposed to be some sort of thrust bearing on it? And the bearings listed under part number BC321J - Rockauto lists these as correct for a slant six as of today - definitely aren't right.
Then I realized I had five sets of bearings instead of four... looks like they sold me a set of small block V8 bearings.

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Matt Cramer
1966 Dodge Dart turbo / EFI project

No cam thrust plate/washer on a slant,,,
Lot of folks do the rocker adjusting screw welded
into the timing chain cover routine.

_________________
Doo Ron Ron and the Duke of Earl are friends of mine.....
https://www.youtube.com/watch?v=uX8Nj8ABEI8

Thanks, I'll do something like that - particularly since I'm going to be using the Rollmaster double roller timing chain.

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Matt Cramer
1966 Dodge Dart turbo / EFI project