Help with Wilwood piston area

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I'm going to order some Wilwoods for my '55 Chevy. I'm looking at the 15" Aero6 front and 14" Aero4 rear. Part numbers 140-15025 and 140-10948. The front calipers come in either 4.04 or 5.40 piston area. Rears only come in 1.98 piston area. I just finished reading the entire brake sizing tutorial sticky but I'm still unsure which to order for my application. It will be primarily a street car with some occasional track days. But I'm building it so that its capable of handling anything I can throw at it.
The car either has or will have the following
AME chassis/strange coil overs
ls3-t56, 550-600 hp.
manuel brakes, I believe stock pedal ratio is 6.42:1
19/20" wheels
245-275 front 315-345 rear tires

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So apparently I didn't scour Wilwoods website good enough. I just saw that the Aero4 comes in 1.98, 3.56 and 4.84 piston areas. So for my system I'm thinking about going with

15" Aero6 5.40 front
14" Aero4 3.56 rear
7/8" manual master

One concern I have is that I am limited on front tire size. I'm going to try and stuff as much as possible in there but thinking a 255 might be max (Morrison ran a 235 on their 55). I can fit a 12" wide rear wheel so I will have a pretty significant tire size stagger.

[malibudave]

A 7/8" bore master cylinder may be a little small for the piston area of those calipers. If you haven't done so already, I would contact Wilwood to see what they recommend as far a bore size for a master cylinder. From some experience with LS1 Camaro brakes front and rear (piston area front is 4.93 sqin and rear of 2.5 sq in) it was at the limit for a stock MOPAR style 7/8" bore master cylinder. This was in a g-body with a 6 to 1 pedal ratio and 0.875"-1.0" master cylinder piston stroke.

With a fairly high pedal ratio of 6.4 to 1, I would also double check to see how much master cylinder piston travel you will have using this ratio. I am not sure if your car is set up with a manual brake system already, but it may be easier to check piston travel with the pedal assembly out of the car so you can mock up the master cylinder, determine the master cylinder piston stroke, and also find out what length push rod you may need.

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After speaking with Ron Sutton, I went ahead and ordered the 15" Aero6 5.40" front, 14" Aero4 3.56" rear. Based on Malibudave's comment above, and having Ron confirm the numbers, I'll be going with a 15/16 master cylinder. The system should provide about 3900# braking force.

I purchased the brakes through Ron, he has been terrific to deal with. I would highly recommend purchasing through him.