Its been talked about befor but I can't find it in a search. I was under the impression that all bronze liners sucked because of a set of heads I had did not last 10k miles. I think they were the grooved liners. Are there any differences in liners or should new guides always be used? This is for a stock rebuild, 4500 rpm engine.

The smooth ones work fine, for 100,000+ miles. Made by K-Line. Use positive seals with them and enjoy long-term start-up-puff-free operation. I personally prefer the Comp or Crane Teflon seals, but they require the top of the guide to be cut to either .530" or .500" OD.

I have been using the K Liner interupted sprial ones for over 10 years without problems that were the fault of the liner.
They need to be installed properly, finish honed & CLEAN, CLEAN, CLEAN!!
I run the intakes at less than .001, exhaust at about .0015
One of the biggest problems with them is improper installation. They are extremely hard to put in with the little kits that are sold as it's almost impossible to get the hole straight.
I use the air lodking stand that K Line has that locks the head with a bushing that centers off the valve seat & it will ream the hole straight.
Almost dummy proof,,,even I can get it right :D
You should not run any bronze type liner with valves that are not very smooth on the stems & the seal I have found to work best is the metal encapsulated Viton ones that look like the ones that come on a lot of foriegn engines like Honda's

Some shops love em' I some hate em'
I would recommend that you use what your machinist is comfortable with assuming he has a reasonable reputation in your area ;)
BTW, we obviously do use solid type guides for some applications also not just the K Liners

Thanks for the info