A couple stupid questions!

[78cheyenne292]

1. will a master cylinder off other 80s or 90s trucks fit on my 78 and do i need one from a 3/4 ton being as my truck is 3/4 ton.. im not doing any towing or anything so can i get by with one from a 1/2 ton

2. were where the speakers originally mounted under the dash were they in the middle.. anyone have any cool ideas on were i can put two 5.25 inch speakers under the pad or anywere upfront.. pics would be nice

3. my gauge lights dont work they havnt since i got the truck and i cannot figure it out but the speakers someone mounted inbehind the switches and one night when i went to turn my wipers on my gauge cluster lit up and my wipers didnt work so i took the speaker out and everything went back to normal but i still couldnt get my light working.. does anyone have a pic of a cluster they could label the main power for the light or a wiring diagram for it all or any other info that might help me out..

thanks a bunch guys!!

[old Rusty C10]

1) i would check the part numbers on the advanced site to see if its the same part number if they are the same it will interchange
2) the dual speakers were on opposite sides of the pad.. the single speaker am radio was in the center of the dash.. most people mount 5 1/2 inch sepakers in the doors
3) no picture but i blieve the haynes manual has the schematic in it

[78cheyenne292]

thanks i think my speakers were in the middle thats were the holes in the dash are.. i was thinking putting them in the doors but there in such good shape i would hate to cut holes.. new doors are slim pickins around here.. is it a diffrent master cylinder because its a 3/4 ton?