In all A,B,E bodies, the engine is offset to the passenger side 1.25". This is normal, and should be left this way - the transmission and rear pinion are both also offset - if you center the front of your engine, you'll have a crooked driveline, which may cause u-joint problems, and you'll definitely have header clearance issues because all the header companies build them to fit with the engine in the factory location. The only exception is the 62-66 A-body, which is actually offset closer to 1/2" at the crank snout, although this number can vary, and the engine is visibly crooked if you look closely - there isn't much room in the early A's, and you're usually stuck placing the engine however it will physically fit.

• Schumacher Conversion mounts - any engine to any K-frame - factory position. These require minor work on the driver side perch, depending on the year of your car.
• DC K - copy the old Direct Connection frame from the 70's. Uses stock Mopar parts, new or from a junkyard. Factory postion.
• Directly bolt engine to 73-up frame with b-body mounts. This is similar to the DC K idea, without welding. The engine installed this way will be 1" too far forward and 3/4" too high. Although it can be made to work by flipping the trans crossmember, it causes various clearance problems which have to be worked out yourself.
• A biscuit mount combination is also possible - 72-down b-body brackets, with insulators from an 80's Dodge truck will allow the engine to bolt in close to the stock height, although nearly 2 inches further forward than stock. This solution requires a plate to be attached to the trans crossmember, as the engine is too far forward for the trans to bolt directly to the crossmember.
• Elephant ears/Motorplate - the is the well-known solution for most drag cars. It's one of the strongest solutions for high horsepower cars. However, since the plates interfere with the front of the engine, pulley alignment has to be modified and brackets must be made to attach the plates to the frame. This solution also induces alot of vibration to the passengers and as such, isn't recommended for daily use.

• The most recommended factory pan is the 67-up C-body pan. It has a stamping of #699 or #187. This pan has a notch in it for idler arm clearance, which can be a slight problem in the a-bodies.
• The standard street Hemi/440 HP pan works, as well as the deep pans that are offered by most aftermarket companies. A possible exception MIGHT be custom made deep pans. The standard pans with a deeper sump all work ok...MP, Moroso,Milodon...

• A-bodies, depending on options, had either a straight or dropped centerlink. Actually, these links are about in the same position, as the attaching method switched from the top to the bottom. There should be minimal problems here, save for the above mentioned oil pan/idler dent.
• Another item to think about is the 67-only idler arm. It's quite expensive, being a one year only part. If it's feasible, it would be best to switch to 68-up k-frame and parts to avoid the expensive idler.
• 73-up frames had many improvements over the 67-72 items, and is the best factory starting point for a build-up.
• Also keep in mind that most underchassis headers will hit the steering column. The #7 tube comes out of the head very close to the column. It often requires that you remove the outer sleeve on the column up to the firewall, to allow more room for the header tube. Although it sounds like a pain, it can actually be done in about an hour.

• The standard trans mount works fine.
• Conversion mounts allow use of the stock trans mounting.
• The best way to mount any engine in a car is to first bolt it to the factory trans mount to locate the engine properly in the car, and then work out a way to mount the engine. Any custom application should be done this way, as a properly located engine saves alot of future clearance problems with accessories.

• Most people on a budget are inclined to skimp in this area. It's not wise. A broken car is less fun than a half-finished one.
• The A-body 8.75 came with small drum brakes, and a 4" bolt pattern that isn't very popular. As for width, once you move springs and wheelwells to fit 10" rims, you'll find you need 7.5" of backspacing. There are only 2 wheels available with this much offset, so choices are limited. Notice alot of a-bodies have Draglites of Centerlines? Now you know why.
• A good street performance recipe is as follows. Use a b-body housing and have it narrowed "about" 5 inches less than an a-body width. B-body housings are still very cheap to start with, and if you get the brake parts, they have 2.5" wide drums vs. the a-body's 1.5" drums. You do at least need the b-body backing plates to upgrade the brakes. Next, give Moser, or your favorite axle place a call and get a set of heavy duty axles to fit your length, having the 4.5" bolt pattern, non-adjustable bearings, and the correct offset to compliment the b-body drum brakes. Doing all of this will end up around $500 without a center. For that, you'll have bullet-proof axles, bigger drum brakes, the more popular bolt pattern, and need less backspacing, so you can use any style of wheel you want. This isnt the cheapest way, but it will save you some headaches later on.
• Another excellent rear-end choice is by Ford...The 70's comets, mavericks, granadas, monarchs, and versailles (possibly others), all have the exact same dimensions as our a-bodies. They all came with 8" or 9" rears with the 4 1/2" bolt pattern, parts are very vailable, e-brake cables are the same, and they're plenty strong. They're only 1/4" wider on each side. Identifying the 8" is easy as it has two dimples the back center, while the 9" doesn't have the dimples, and also the 9" has a bulge to clear the ring gear. Combo u-joints are commonly available at parts stores. Although the Ford rear isnt a Mopar part, many people with small wallets will see it as a god-send when money is tight.

• As with most swaps, a custom length shaft is required. Instead of shortening a stock one, spend the extra dollars on a bigger one with the bigger u-joints. It's cheap insurance. 
• As far as OEM shafts that fit, so far, I've been told that a shaft from a two wheel drive 84-90 Ramcharger or short van with a 904 will work, and you can just change the yoke to work with a 727.

• This really isn't a very big deal. You can spend the bucks on one of the custom rads now offered, or you can simply look through the junkyard for a rad with similar dimensions and make your own mounting brackets. In most cases, a flat piece of metal tacked on to the radiator frame will work just fine. This is pretty much up to the builder and the rad chosen though. Mine is from a fullsize Ford 4 wheel drive and works great for less than half the cost of a custom one.

• Torsion bars should be upgraded to bigblock versions. 0.890 bars or better - strip only cars can use /6
• Upgrading to front disk brakes is a good idea. The cheapest method is to use 73-up disk brakes from a donor car. This will also get you the 4.5" bolt pattern on the front, to match the rear you may have built from the above information :)

• Schumacher Tri-Y 
• Hooker Super Comp Fenderwell
• Hedman Fenderwell
• TTI 1.75" and 2" versions underchassis - 1.75 is for stock head 383/400 only and both require manual steering.
• Pro-Parts partial fenderwells
• Stahl fenderwell
• Factory A-body bigblock manifolds
• B-body HP manifolds
• Accurate LTD's custom casting
• B-body 1.75 underchassis - only fits with stock head 383/400 and manual steering.

• Rear tire clearance varies depending on the year, as the coupe style cars have much bigger wells. Currently I only have specific info on the sedan/hardtop style.
• You can fit a 9.5" total width tire in the stock well. 
• If you just move the springs inboard it will allow an 11" total width. 
• If you move the springs in and the wheelwells into the frame you have  13.5" total width to play with.
• If you're building a car basically from the ground up, you might as well move the springs and wells while your car is apart. Lots of power does nothing if you can't get it to the ground.