[KOG]

75 would have 4-1/2 lug pattern so the wheels interchange with full size Chrysler and also with Jeeps. There are lots of decently wide aluminum wheels on Jeeps so you might want to start looking there. It would have been a 318 car as the only 360s were police package, so rare as to be non existent and they didn't come in SE. It'll have a 2.45 gear 8-1/4 axle which works well with the 360. Front brakes are the same discs used with Hemis in B bodies so they're adequate. About the only chassis mods it would like are large antiroll ("sway") bars front and rear. 73 bumpers fit the body better if you can locate a pair of them. Power seats from a later Diplomat or 5th Avenue are bolt ins and are much more comfortable than the stock SE buckets. Putting the battery in the truck helps handling and so does aligning it with about 1/8 degree negative camber, all the caster you can get and 0 toe in.

 

[ImperialCrown]

Here is a useful wheel measurement guide and cross-reference:
http://www.crawlpedia.com/bolt_patterns.htm
The 5th character of the VIN would be the original engine code and it would also be stated on the underhood emissions label.

 

[dana44]

Nice link, explains a lot. Easiest way to determine how much backspacing you can do is with a straight edge about 24 inches long and a ruler. Set the straight edge against the face of the drum so it sticks out on one side and measure 90 degrees side to side of the edge sitting against the drum, so, if the straight edge is laying against the drum and at the tip of the straight edge I have five inches clearance to a wheel well edge or anything inside the well area that is inside the edge, I can have that much backspacing, and if the outside clearance at the same time is three inches anywhere on the inside of the outer wheel well lip, then the outside spacing can be equal to the two sides, but leave a minimum of half an inch each side (inside and outside) for clearance.Be sure to measure this way all the way around the inside, don't want one little spot to touch the tire, it will wear, scrape, or even cut the tire, which is not a good thing.

 

[TheMyth]

Thanks for the help! I've got my new wheels and tires already here, now just waiting on my front end rebuild kit and I should be pretty good and ready for spring cruising...if spring will show up!