We needed to deliver the heads to the machine shop bare to avoid being charged the labor of breaking the heads down. If you’ve never pulled a head apart, you will need some kind of valvespring compressor to get ’er done. The compressor is even more important when putting new springs in. In our formative years, we have been able to get the old springs out using pliers and screwdrivers. Yeah, it’s butch, but it is doable. Then we tried to install the new ones using the reverse method. Yeah, nope, not happening, and that is not to mention the damage that might occur to the new parts, thus costing more money. This Performance Tools compressor is our favorite type. The large jaw uses the valve or combustion chamber itself for leverage rather than just prying on the spring. This is the safest way to do it and avoids damaging any of the new parts upon reinstallation.