Let's say I had a head that was to fit a 1.550'' valve spring, but the valve springs I need are 1.46'' would they still fit?
Thanks

Drag,
I would try to find a 1.550 spring that will give the proper spring pressures you need. The main reason is if the heads are cut for 1.550 springs, there will be nothing to keep the smaller diameter spring from walking around, unless you use a spring cup, and then you will lose some installed hgt. Take a look at the specs of the required spring and then go searching all the different manufacturers site. You should be able to find something that will work.