ST4 heads on an S4?

[DTR]

Scratching my head trying to remember......the S4R has the ST4 (and ST4S) heads....right?

[Speeddog]

AFAIK:

S4R and ST4s are same heads, valves 36/30, short duration intake cams, std 4V exhaust cams.

S4 and ST4 are same head,  valves 33/29, short duration intake cams, std 4V exhaust cams.

All of the above are the 'dropped cam' heads; exhaust cams are ~10mm closer to the deck than SBK heads.

[DTR]

Thanks for the speedy reply.