Whipple Pulley / Belt Size Questions

[Bandit429]

Hello,

I know this has been asked numerous times, however, I keep finding different information and nothing seems to be concrete enough.

I currently have a Stage 2 Gen 5 3.0 Whipple 6-rib stock balancer 3.875" pulley for a 2017 Mustang GT which is my daily.

My question is:

What is the smallest pulley I should run with 93 and also E85 to reliably drive as a daily with some strip time?
Original plan was a 3.75" for 93 and the 3.625" for E85. Should I just buy the 3.5" instead of using the 3.625" or is that pushing too much? Or should I change both sizes to something else?

Also, I am having a hard time figuring out what belt sizes/part number I would need for each pulley?
I keep finding different information and nothing seems to be concrete.
My kit came with the K060824 belt which was installed March of '21 using the longer belt routing.

Current mod list:
Stage 2 Gen 5 3.0 Whipple 6-rib stock balancer
Texas Speed 1 7/8 LTH w/ Cats
Boundary OPG and CS
JLT Catch Can
MBRP Catback
3.15 gears
3.875" Pulley
72lb Injectors
93 Oct on Whipple Tune

I currently have waiting to be installed:

Lethal/Division X L2 Return Fuel System dual Walbro 465's
DeatschWerks 1200cc Injectors
Griptec 3.75" Pulley
Griptec 3.625" Pulley
Possibly deleting Cats

Thanks for any and all help anyone is able to give.

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[Whitedevil95]

Seems like you should stick with the 3.875 on pump gas to be safe. You really dont want to push things too hard on pump.