Has anyone used Ford Performance's stainless-steel valves, specifically M-6507-J302 (I) and M-6505-G302 (E)? Both have OAL of 5.078, 11/32 stems, .385 tips, and single, square-groove? The intakes are 1.94 and exhaust 1.54. I recall reading they are made in Argentina, as many/most valves now are. 

I've used them in E-7 SBF heads.  Also used in the J-302 aluminum SBF heads.  I have not used them in a Y Block head.  Usually you need the .250" tip instead of the .390" tip which is for the rail rocker arms that fit over the valve stem tip so that you don't need a guide plate.  You will need to check the valve train geometry on the Y if you  use the longer tip length.  Why not use a Manley SBC valve in either +.100, or +.200 for your Y?  They are cheap, readily available for street builds.  Joe-JDC


JDC

My primary concern is quality. I guess if Ford uses them in $10,000+ crate engines that come with a 2-year warranty, they must be ok. As far as tip length is concerned, that must be ok as well, as Tim McMaster has used 351W valves (all have longer tip) in Y-block heads. Took awhile to find what I was looking for. 

Joe, did you use rail rockers on the E7 and J302 heads?

Bolt down rocker arms on E-7 heads, roller rocker arms with guide plates and hardened pushrods on J-302 heads.  Joe-JDC

JDC