Other than the programming, what would cause a lean condition at WOT?
I have a GMS MAF sensor Im thinking of getting rid of, could this cause it to run lean?
I have read they are not user friendly with custom programming.

Car dynoed at 403.3 HP in Florida.
This is a 383 Stroker with AFR 210 COmp heads and Comp 236 242 112 LSA cam.

I want a 27+ more HP out of it NA.

 

Yes, GMS can cause such condition. Mainly because that excuse for a MAF was designed for stock or close to stock cars.
But let me ask you this... What makes you think it's creating a lean condition? The dyno graph? How lean and which RPM range?

 

I'll send you an e-mail titled GMS MAF lean condition
you can look at the graph of the wide band o2.
#3 was Left o2 bung and #4 was right, taken from the y pipe.

 

I tried sending you a reply, but it says your mailbox is full and cannot accept my couple of sentences long message.

I asked you if you could change the scales so that it
shows AFR versus RPM instead of AFR and RPM versus time? Also, please remove that AUX from the graph to make it cleaner.
Thanks.