Thermostat alignment

[M25VAN]

Just about to put in a 74c stat as summer has finally arrived. Old ones used to have a flow direction marked on them but the new one and the one it is to replace don't. Does it matter how it is fitted? Obviously not upside down. I'm wondering if one way will give a better flow...
Also is it wise to put a small hole, say 1/8th inch, in it as they don't seem to come with this any more either.
Thanks

[simmitc]

Yes, drill a small hole, helps tremendously when filling the system. As long as the stat is the right way up, it shouldn't matter much on orientation, although I always fit the domed bar at right angles to the housing outlet so that there is as much free-flow as possible. However, I doubt that it really makes nay difference.

[M25VAN]

Yes, that makes sense, I'll go with that. What made me mention it was lack of flow through the rad. I'm sure before that with the stat open and a good rev of the engine I used to see a rush of water flow across the top of the rad. Don't get that now. I've done the usual flush throughs but maybe it is the block silting up....