The positive seals will use more oil. They only work good if the valve guides are new.

Sorry, can't remember which seals they were but when I get back next week will check the invoice to see if they are ID'd.

DD, not sure on why you think the posi seals use more oil etc? They are a positive seal around the valve stem (and guide) so actually help prevent nearly all oil from being sucked down the guide. I know from 1st hand that my engine went from smoking the shed out if left to idle for any length of time to no smoke at all after having the seals replaced (and the guides weren't touched).
The umbrella types have a bad habit of riding up the valve stem until they sit just under the retainer, thus doing sweet FA to stop oil being sucked down the guide.

Positive seal fails when the stems rock back and forth, because they are attached the the guide and to the rocking stem.

Most of the oil comes down from the retainer, which is why umbrella seals work so well. They dont' rely on a seal to the guide, they just ride up/down.

My old umbrella seals slid much easier than the new ones on the stem so maybe new umbrella seals will help, but seeing as I already have the rocker cover/rockers off and seeing that valve seals are pretty cheap - it wont hurt to use positive seals.

Let us know how it works out. You should be able to tell right away after installing them.

I'm kinda waiting for ssskiwi to reply with what type of positive seal fits A12 stems but If I cant get a reply before Sunday and I'm not busy I'll just put the new umbrellas on.

eBay? From bprojects.

Or just go to repco (or similar), they're a 7mm valve stem (best to check that), see what they have in stock?

So the valve stem is 7 mm, whats positive valve stem seal will fit good on the stock A12 valve guide? Will L series ones fit?

I got a mic. onto the guide and its close enough to 12mm. All I need to find is a seal from a car with 7mm valve stems and 12mm valve guides

I got a mic. onto the guide and its close enough to 12mm. All I need to find is a seal from a car with 8mm valve stems and 12mm valve guides