[dsraven]

for the distributor, if it is already installed and set up it is still easily turned without pulling the distributor out. simply turn the housing the same number of degrees as it is to the next wire tower on the cap, then move the wires over so they are clocked the same as they were before. it is easy if you mark the housing where number 1 cyl wire tower is on the cap and also the cylinder next to that in the direction of rotation you want the dizzy to be turned, so drop a mark down from the tower wire connections and transfer the marks onto the metal part of the dizzy. then turn the engine by hand to line up with number 1 cyl on the timing mark pointer, then take the cap off and see if the rotor is pointing to that mark or if it is 1/2 a turn out. if it is 1/2 a turn out just turn the engine another turn to the timing pointer and that should fix that issue and the rotor should be pointing to the mark you made on the dizzy housing for number 1 cyl. now simply turn the dizzy housing so the rotor lines up with the mark for the next cyl. put the cap back on and move the plug wires around the cap by one tower location. if you planned on 2 tower locations of rotation simply mark the housing 2 locations over. it goes without saying that you will want to confirm the timing after doing this, thats easy enough though. remember the electrical plug on the opposite side is going to be closer to the firewall when the dizzy is turned so the vac advance clears. you gain one and lose the other
with all that said remember that you will need some room to remove the dizzy cap to do maintenance, blow out condensation after an engiine shampoo etc etc. sometimes this happens at the least opportune time, like at the car wash. it sucks when there isn't enough room and it was your own fault.......trust me......when you "engineer" something and then you have to work on it later you understand your shortcomings and dont do it the same next time
seat base idea. if you need to tunnel the floor just cut out the area you need and possibly the old base that is left intact can be enclosed to provide a new seat base for the donor seats. just an idea and maybe it wont work anyway. like joedoh says, cut it off, flatten the part left. unless you plan to keep the floor bare nobody will see that anyway.