Converting old Peavey amp to something modern

[chip]

I have gutted a 100W 4X6L6 old Peavey Deuce and converting it to a 50W all tube amp with 2X6L6.

The main question I have is can I use 2X 50uF "500V" caps instead of the 4X 100uF 350V shown in the schematic?
Here is the voltage measurements of the input trany unloaded.  So this is just the input trany w/o anything hooked up to it.
RED - RED/YELLOW = 392 VAC RMS
VIOLIT - YELLOW = 59.2 VAC RMS
BROWN - ORANGE = 6.97 VAC RMS

Any other comments about the modes on this power section are welcome.

[navdave]

You could but you would be pushing those 50uf 500V caps to the limit. Your really not changing anything because two 100uf 350V caps stacked= a 50uf cap rated @700V.
Also if you are gonna be using the same output transformer be aware that your output impedance will be doubled, 4Ω will be 8Ω, 8Ω will be 16Ω, 16Ω will be 32Ω.
If those caps are good leave them alone mess with the preamp design and voltage. With those kinds of voltages you can build almost any kind of high gain amp into that thing.  
Check out this page http://www.el34world.com/charts/Charts.htm
Also pulling two out of four power tubes will make your b+ jump up about 20 to 30 VDC.

[sluckey]

The main question I have is can I use 2X 50uF "500V" caps instead of the 4X 100uF 350V shown in the schematic?

I wouldn't. 392 X 1.414 = 554v.

[chip]

Ok, thank you.  I'll stick with the 700V capacity.