[hajime]

My small block 363 with Quick fuel carb SS750 is good between 1st and 4th gear.
It has good response and stable AFR around 12.2~12.5.
But I am always frustrated at the time I fully accelerate at 5th gear in the racing track.
It reach around 130~140mile, AFR is around 10.0~10.5.It almost not accelerate smoothly. Until 4th gear it has been fine.
I guess it is short of air at the high speed range like over 130miles.
AFR show me "Too rich".
But my carb is 750cfm ,it's a little too big one for 363.(363/2*6500/1728*0.9=614)

I have little knowledges about carb setting.(and English,because I'm Japanese)
What should I do ?

Please someone give me any advice.

Jet setting is kept original from the factory.

Superformance Mk3, 6500miles ,I love driving at racing tracks.