Missing Valve seat

[Tom Wesenberg]

Diamond A and B blocks had seat inserts on the exhausts from the factory.

I have a diamond A block with a B cam and no valve seats other than the block.

 

[mike657894]

I have a very late 1940 diamond block it has just exhaust hardened seats. when I put new valves in the hardened seats were pretty much a drop in. the intakes needed about .030 of the stems to fit right. im guessing the seats were worked in from many lappings.

 

[TerryH]

I also have a diamond A block with standard factory seats.....I keep hearing they were hardened, but not true in many cases....