Red head flow figures

[lxhatch_jim]

Hi lads. I'm chasing flow figures for a stage 4 YT head for a red motor. I've called YT and a thousand head reco/port shops but the best answer I have to date is 25-35% above standard? What's standard? I'm going crazy.

Most of the shops said they "haven't touched 'em for years"

Does anyone have any numbers/estimates from back in the day?

I think I was born 30 years too late - I've missed the boat

Cheers
Jim