I posted this last night, but it must not have shown up ...or I didn't press "post" 
For the rear, you could go with an 8" out of a V8 falcon/Mustang/maverick(?check the width?), some flex-i-form fiberglass leaf spings (or maier/mustsnag plus steel if you save some money) , a panhard or watts link (your choice), nice shocks, your favorite type of LSD, and some under rider traction bars (optional with torque absorbers from speedway motors), and install the crown vic rear discs. if the rear is too wide, you can use some moderm high offset wheels. This should hold up nicely to a mild 302, especially if you are not drag racing it all the time. (I am planning similar for my 67 mustang, but I already have the 9" housing). You "can" go further with leafs isolating all the various suspension requirements off the leaf spring, but at that point, you might as well go 3-link or 4-link...
All that is no longer cheap unless you run upon deals, which is why most say 3-link or 4-link and coil overs. Unless you got some really good deals, you probably have $1500-2000 in the rear alone (since you have to buy the housing too)
I am hoping to just find a ford rear end that with minor mods (I dont mind welding things to an axle) I can bolt in and get rear disk as well as a bit of an upgrade in terms of strength. The 99+ explorer rear ends have peaked my intrest as they are disk and from teh looks of it you can swap axle tubes around and you have somthing that is the proper width.
There is also what is available at the local pick and pull.
I was there yesterday and they have a complete 351 from a 88??? F150 for cheep. It includes everything. It was funny as it was sitting next to a 5.3 mod motor and the mod motor looks HUGE comparatively. It was also weird to see the large open area between the heads in the 5.3. If you could get a more "common" intake manifold for the 5.3 it would help alot but the thing is sill just huge with the heads being as large as they are.
I chose something close to option A for my 60's muscle car. The biggest reason is that newer technology is the same price, and it is darn near impossible to find decent tires for 15" wheels. Options are BFG Radial T/A, crummy all-seasons, or Track-only race tires.
I also enjoy my bolstered seats.
Very good argument there!!! For option A
Tim
If you are still reading this I had an interesting project for you. Get two cars of similar condition that are both down market 60's sedans (like the falcon or comet or ????) and then build one to an A option and one to a B option (as noted in my first post) A very good series of articles could be written about the trials and tribulations of both builds, reasoning for why things were done (old and new school) and finally how do the two cars compare after living with them for a while.
Well, the explorer rear with two passenger sides is probably going to be the closest you can get there. I looked at that too. If my calculations are correct, the width (with 2 short axles) is going to be about 56.625", which should be pretty close for a falcon/comet. I'm sure you'd have to relocate the spring perches though, but the usually are a pretty great axle with 3.73:1+ ratios, limited slip is common, 31 spline axles, so it will handle the hp.
The only negative I have heard (and not 100% confirmed) is that when you put a passenger side axle on the drivers side, that you "can" have problems with early failure....something about the axle taking set to it's original rotation and not liking being rotated the opposite way long term. On the plus side, you can buy 2 rears cheap, made a short one to use, and a long one to sell (62.375" overall if my calculations are correct.. that could be used in larger cars or trucks) and almost have a free rear.
It is not popular these days, but the drum brakes (with good shoes) in thae back aren't THAT bad unless you are road racing and need the extra heat dissapation and some will even argue that drums are better at that. Finding a cheap V8 falcon rear might be a challange though...
I just like the easy pad changes with disk. The drums in my explorers were fine in fac tyou can adjust them up so they work better than the disks but easy pad changes makes them part of my "want list"
Your measurements / calculations re the rear end sizing is what I got as well meaning there could only be about 1 5/8" total difference in the axle or about 7/8" wider on either side. I am sure that this could be fixed with wheel offset. Probably would lend its self to a front wheel drive offset and that may actually open up the wheel choices alot.
I had a '63 Falcon Sprint. I can't say I liked it much. It was beautiful. I would have been happier with a '64 or 5 where all the mass produced go faster suspension for Mustang stuff would have bolted on. I hated the spare tire laying flat in the middle of the rtunk. It made the runk effectively smaller than my '68 Ford Cortina. It had the same looking console as that Falcon. People were putting Lincoln Versailles and Granada/Monarch axels in them then for rear discs as I recall. I sold mine pretty quickly.
So I went and looked at said car and it was much worse than I think the owner realized. On first glance it was a nice car. One respray and what I would call driver condition. The bad was under the car. Rot to the rear leaf spring mounting area and the front frame had rot back by the firewall. I don't mind replacing sheet metal but this was structural and would require major surgery. The owner was a bit weird about it as well. I got the feeling they knew about it and were playing dumb so I passed. I did not even offer a low ball number. My gut was saying walk away.
So back to Craigslist. The hunt continues.
