Recommended valve guides: solid or spiral grooved?

[kgroombr]

What type of valve guide would be recommended for a 140 head? There are two types available: solid iron, and spiral grooved iron.

From my Internet research it sounds like spiral grooved is ensures good lubrication, but I have read that solid is better for durability.

Thanks,
Ken

[monzabug350]

It depends on what you intend to use the car for,race/street.The grooved guides are the better choice due to better lubrication which will improve durability over time.I have used them in the past on street and race cars and have had no problems with them.Just make sure you have the proper guide/valve stem clearance and you should be good to go.