Strange findings in 305 sbc heads

[travis]

2C4B1695-174A-4B28-8B4C-854F81622B43.jpeg

I went to pull the valves out of these 601 casting 305 heads...was kind of surprised to find 1.84/1.50 valves with multiple lock grooves, and single groove locks. These heads appear completely OEM...as many stock sbc heads as I have worked on I have never seen anything like this. What’s going on here???

This is the intake and exhaust valves I pulled from the first cylinder, but they are all this way.

Side note...it’s absolutely sickening how much bigger and better the port shapes are on these 305 heads versus these E5AE and E7TE ford heads I have around here. I was pulling the valves to test fit them in my ported E5AE heads but the tips are pretty battered

[rustbucket79]

Any abc head pre vortec had the 2 groove valves, the lower groove is where an o ring seal sits. 1.84/1.50 is the factory sizes

[travis]

Any abc head pre vortec had the 2 groove valves, the lower groove is where an o ring seal sits. 1.84/1.50 is the factory sizes

Well, I feel like a f’ing idiot now I’ve been staring at way too many ford heads lately apparently

[mag2555]

Yup, 100% normal stuff, in fact Pontiac valves have the added lower grooove for the oil control O ring also.

You had better not look at Mopar big block 3/8" stem valves as there 3 groove keepers as that will really make your head spin, lol!

Just joking with that comment , as you say sometimes we focus on one thing for so long it's like we have blinders on !

[F-BIRD'88]

I believe you will also find that the exhaust spring seats are deeper too. By about .105".
So if eliminating the thicker exhaust rotator retainer for normal sbc retainers, add a .060"+.030"+.015" (3shims) stack of spring seat shims to compensate the spring height.