i see that some seals come with the steel wrapping around some of them,have anyone tried these yet?what would be good set for hi po street eng?thanks

Their are several different brands and different type material used for valve seals now like your describing, don't buy the old race Teflon ones for street use
Viton works well on the street and for drag racing

thanks,i will be using dual springs i see comp has some viton steel jacket ones,are there any machine work needed for these seals?

I'm thinking you might be OK with the garden variety black umbrella types (tall ones go on the intakes).

Measure the inside diameter of your inner spring and then look at the Viton seal specs. that Comp offers,(maybe check with Goodson also ) they sell more then one inside diameter dual spring. If the inner spring is at least .060 larger than the outside diameter of a seal that is offered to slip or press onto the stock valve guide outside diameter buy them
I'm thinking that the press on Viton seals come in three different inside press on sizes, .620, .530 and .500 for 3/8, 11/32 and 5/16 valve stems
I bought the cutters and all three size guides so I can prepare, machine, the guides for the seals I need on the race motors I build instead of having to take them to a shop and wait