You'll be moving the master cylinder forward requiring you to relocate the brake lines...usually doesn't come out very well and you may end up replacing them...not a bad idea for a 40 year old car. I gotta say, I had that setup and went to front power disc and I've been driving this thing like crazy! What a difference. You should be able to get a front disc conversion kit for 700-800 with all new lines and everything you'll need.
On a scale of 1-10 in difficulty, I'd rate it a good 6-7 depending on your ability.
