Valve seat angle is 45, valve face angle 44-1/2. Set the intake valve first to the correct recession. Measure that and set the exhaust valve stem height to match the intakes. Yes like any valve springs there are two test, tension with the valve closed and tension with the valve open. If you head has had intake seats installed in the past it make have rotators. If it does then springs will not be the same neither will the specs be the same. I need a casting number and a little bit of other informtion. Oliver had an exchange program for those early heads where they installed a sleeve in the exhaust port and put a Fleetline 88 diesel valve in. IF you have one of these heads you CAN NOT install exhaust valve seat. Send me an Oliver and a Waukesha casting number. I do not remember the specs for the valve springs in my head. If you do put intake seats do not use a plain cast iron seat. Questions?