Fitting some 1.560 inlet valves.....?

Hi, it happens I had found a pair of new Black Diamond inlet valves slightly oversized (1.560) in my box of spares, should (could)I fit them in a head I am refurbishing , will that bring any improvements, and mainly must I regrind the seats , any ideas where to find the proper tool if needed??

This work was done on a Triumph head but some of the same things apply. First picture just cutting the seat in and the outside edge of the carbide inserts have shown were alum. needs clearing away for good low lift flow.

If you view the album looking at the captions you can kind of work out how one goes about it. Lots of work with a single insert that has a radius at it's outside edge for blending into the chamber. All done this added 10 HP to the old head.
Here you can see the old recessed seat all gone when the work is done.

Here is a link to the album.
http://s116.photobucket.com/user/norbsa ... %20install

You can fit the larger valves with no problems, as long as you aren't using a high lift, long overlap cam. With some more radical cams, you might have a problem with valve interference between intake and exhaust, and might have to sink the exhaust valve to get clearance. Should be no problem with stock or most street use cams, but something you need to check if using a more radical cam. You will need to grind (or cut) the seats for the larger diameter, and ideally, you'd open up and blend in the throat to match. A good 3-angle valve job would take care of that. The 1.560" intake is about as large as you can go with the stock seat insert.

Ken

I bought a Neway kit on ebay. Used it, sold it right back to someone else for the same price including shipping. I explained this in honestly in the description and it sold in a few hours.

Do a little research to make sure you get the proper cutters. Some are adjustable in diameter. They work real good so be careful not to go too deep.