What kind of master cylinder do you use, for clutch and front brake?
Pictures, please

What calipers and how period correct?
Bill

you're right, brembo P08 oro, on my race F1

This is kind of like the current dyno discussion with too many unknowns, but maybe there is a language barrier. The original (13mm?) clutch master (in good working condition) is fine. (2) P08 calipers are probably adequate for not too serious racing with 16" or 18" wheels and tires, 280 rotors, strict vintage racing rules, and a "limited" budget. In which case a 15mm master is probably the best choice. Can't remember what size the stock F1 front master is, but if it is not 15mm, this might be a good choice: https://store.bevelheaven.com/Brake-Related-Parts/15mm-REC-Brembo-Master-Cylinder-Front-Brake/ I am basing that size on Vintage Brakes good ratio chart: http://vintagebrake.com/mastercylinder.htm More serious braking involves more serious changes, but may not be legal under the rules you are racing under.
Bill

Thanks, in france, vintage racing rules are pretty strict with period brakes required ( 2 pistons calipers) and period wheel sizes....
My question was about the best MC for those brakes ( we currently use PS16, with 2 P08)

Philippe

Hi Philippe,
I'm guessing you have a problem with that master? The PS16 master is the 916 style master was intended for use with (2) 30/34 calipers working on 320 rotors on 17" wheels with modern tires, same as on my 748, which had very good two finger power and feel. I used that same master on my '80 bevel with (2) P4.32B calipers (the earlier black (4) 32mm piston calipers from early 851's) on 280 rotors on a 2 1/2" wide 18" rim. That combination had ok feel, but I had to be careful not to overpower the narrower "street" tire. I still don't know what wheel/rotor combination you're using, but for your P08 calipers, I'm sticking with the recommend 15mm master cylinder working on good organic race pads, like Ferodo CP1's. I have yet to find fault with that Vintage Brake ratio chart.
Bill
p.s. If anyone else wants to jump in here, please feel free.

For a pair of F08 calipers a good choice is the 15mm master cylinder for racing.( Did I just agree with you Bill?)
F1s came with 14 mm masters and got mushy when used hard. Still OK for street use with goof feel.
For reference the bevel twins came with 15mm and were known for good brakes.
-cranky-

Actually, it's Michael at Vintage Brake you're agreeing with, but still, I do feel very honored.