Seems to me a bigblock should be close to the same weight as an old stovebolt six,maybe a little heavier. I'm thinking it'd take some modifications but I remember seeing a gear-drive steering re-locator advertised in Rod-n-Custom recently. I'm looking for the ad now. Basically,you cut your steering column down at the firewall,you connect this box to the steering shaft,and it moves the end that goes to the steering box up,down,or to either side several inches for clearance.on the outside of the firewall you run a steering shaft to the steering box,connected with a couple of u-joints. That,combined with moving the steering box out a few inches should give you plenty of room for whatever exhaust you want to run.Another option might be the conversion to a Toyota steering box.There's kits for that one. Either way,you can run manual steering,one with the stock box,and the other with a newer box. I'm not sure but I think the Toyota box is a little quicker ratio. Lotsa options available to you.
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