If you want to run a split reservoir M/C with a booster,you can mount it farther back than the stock one and just use a longer push rod from the pedal to the booster. Then you'll have plenty of clearance,and you can put a new filler hole under the seat. I did that on my '54 2 Ton.
Speed

1954 GMC 350
1957 GMC 1/2 ton
1962 Chevy C-30
1952 Chevy 6400 dump bed project truck
'98 Harley FLSTC
'66 Pontiac Catalina
'76 Chevy 1 ton Duallie
'84 Bronco II
'78 Dodge W-200
'81 Toyota 4X4 truck