Big block / small block Rocker question

[K.O. SWINGER]

So okay pretty simple question but all I've only really worked on is small blocks what is the difference between a big block rocker arm and a small block rocker arm if they're both 1.5 I realize that the spacing will be different due to the larger head of a B or RB but it's a rocker actually different? It must be there sold under different categories but what's the difference. Thank you.

 

[brian6pac]

BB have offset push rods, SB are centered. Not sure what it is, never measured them.

 

[K.O. SWINGER]

BB have offset push rods, SB are centered. Not sure what it is, never measured them.

Interesting, thank you. Are the shaft diameters the same?

 

[brian6pac]

Interesting, thank you. Are the shaft diameters the same?

Yes 7/8"

 

[pishta]

This came up on the dieseling sound thread. I wonder what the difference is between the stamped rockers? Slight offset can be beneficial even on an LA
340 compared to 383

 

[LS&S]

I had the same question, so I compared big block stamped steel rockers on right to small block on left in pictures below.
440 Big Block rockers are significantly longer from push rod indent to valve tip than 318 small block rockers. Also, Distances are different from center of fulcrum to valve tip and push rod indent.

Top View

 

[PRH]

Yup, BB rockers are longer.