This kit contains OEM style stainless one piece forged valves with uncoated stems. The guides are C67410 manganese bronze, which are able to be sized with a reamer, unlike the harder C630 bronze guides. These guides were developed for easier machining, and still have excellent longevity.
These guides are not finish sized, and must be honed to size after installation to provide correct clearance. Recommended clearance in aluminum heads are as follows:
Intake valve to guide clearance: .0010"
Exhaust valve to guide clearance .0015"
These clearances can be easily obtained by finish sizing both intake and exhaust guides to .3115" as the exhaust valve stem diameter is .0005" smaller than the intake. Manganese bronze guides can be finished with a suitable reamer, or a rigid mandrel type hone such as a Sunnen® P190. These recommended clearances are offered in conjunction with a thin film of moly type assembly lube on the stem on installation, the assumption that the guide is finished straight and true, and that the SEAT IS RECUT TO BE CONCENTRIC WITH THE GUIDE CENTERLINE.
*Kibblewhite HSS .3115” valve guide reamer specifically designed for these guides is available from our shop, part # GR-3115, for $67.36.
If you find that you need an oversize guide PLEASE STOP and contact the shop. We will exchange for the oversize you need at no additional cost.
Machinists note: Our method of sizing these guides is using a P-180 Sunnen Honall with PK-10 adapter, BL10-308AS mandrel, with L10J69 stone