I need to Know what valve stem seals i Need

This is one of those things that pops up during a rebuild. I had ordered some crane cam valve stem seals, and they fit over the valve, as far as that dia. However they dont seal at the bottom where it fits over the valve guide area.

So, i called summit to try and order some correct seals, and they need to know the valve dia.......And i need to know that they will fit correctly at the bottom as whell.

Can anyone tell me the correct ones? I have gt40 p's.

the trickflow ones that came with the spring kit fit great, but i got brake cleen on them.

ok, thanks. Help me understand then, how they keep oil out? The type i have now on the heads are trickflow, and they seal tightly around the valve guide at the bottom, in fact they sort of snapped on.

These Crane type fit great around the valve stem, but like i said, the bottom does not fit tight at all...it has quite a gap.

In my mind, it would seem that they would just stay in one place on the valve stem, not stay with the head, and also they would not keep oil from going into the valve guide from the bottom.

ok, just for future use, if anyone searches this.

Here is the frpp number
FMS-M-6571-A50