I did a 350/350 in a '51. Here is what I recall. The inner fenders are fine..lots of room. Fan to rad clearance is actually too much, not a point to worry about. If you start at the tranny mount with the engine and tranny together, the first critical measurment is to get the tranny near the floorboard, but not touching. Position it and make a temporary mount. Using jacks, adjust the engine to a level plane. This is a combination of forward enough to fit a distributor in without firewall issues, and level to the eye in the engine compartment. The V-8 will always look like it is sitting way too low but it isn't. Again, unless you "re-hump" the floorboard, initial height is determined by where the transmission meets the floor..everything else come from this.
My HEI just cleared the firewall..no chopping required. There should be no chopping on this swap, there is gobs of room.
I swapped and moved my steering box and installed a different column...the header to box fit can be a beast. Someone will tell you what headers to use that allow a stock box. The front to back measurement of the engine might be critical if trying to use a specific L/H header and stock steering box.
I never felt the brakes were an issue with a swap to a larger engine. If you go so darn fast with your new motor that you can't stop, maybe you deserve whatever happens to you.
Stuart
