[Chevypoor]

You need to measure this clearance. With valve springs off (exhaust and intake on #1) install the valves. Then install the valve seals. It helps to have a valve spring micrometer as it makes this alot easier. If you are carefull you can hold the valve tight on the seat while holding the retainer and the valve locks up in their groove. Now measure with a small rule the distance from the valve seat to the bottom of the retainer. Take the retainer off the valve and measure the how far the valve lock pocket projects below the bottom of the keeper. Measure the distance from the spring pocket to the top of the valve spring seal. Now add these last two measurements and then subtract this number from the distance from the valve spring pocket to the bottom of the retainer. This is your clearance from the valve seal at zero lift. Multply your rocker ratio times the gross lobe lift on your cam card. This your max valve lift. Subtract your max valve lift from your zero clearance. If you have atleast .070 left you are good. If not then you need to have your guides turned down until you achieve .070 clearance.