What are these reamers for?????

[andywander]

Exactly - little smaller than 8/16" and just a scosh over 2/4ths

Fixed it, thanks!

[nickel-city-fab]

They are all less than 3/8" diameter, so not really that big.

Hrrmm, OK. Call it an optical delusion. Carb reamers, or as LKeithR said, maybe valve guide reamers? ISTR most of the classic V8's used 5/16 or 3/8 valve stems

[luthor]

That depends on what you call a classic V8, Ford and Chevrolet used 11/32" - 0.3438"

[nickel-city-fab]

That depends on what you call a classic V8, Ford and Chevrolet used 11/32" - 0.3438"

Chevy small block used 5/16 valve stems. (going by memory)
Big block was ... bigger.

[Ron43]

http://www.chadwickreamers.com/products.php

I have bought long expanding reamers from the above people for SU carb throttle shafts.
Ron