Hampton VA - Nice place. Used to live between Chesapeake Ave and the hospital.
The Monte you are specifying there is called a G Body. This model line includes the regal, cutlass, malibu,grand prix, etc of the same years. The front track width is a very good fit for the AD series trucks but the devil is in the details. Unless you like a challenge like me, I would suggest using an IFS kit on and AD truck. The engine and trans from you donor can work fine and the 4.3 is a good candidate in this day of high fuel costs. The problems that present themselves with the G body subframe/clip include steering box interference with radiator/core support, need to fab a new core support crossmember, mechanical fuel pump clearance, motor mount locations, and I am sure I could remember more but some I have tried to forget. If you want to see how that modification goes you can view the pictures in my picture trail album or go to
http://www.enjenjo.com/frameclip.html. If you are not mechanically gifted or demented then this mod is probably not the way you want to go.
The rear axle for the G body cars is right at 58 inches and is a bit narrow for use on our trucks. The 70-81 camaro/firebird rear axles are the typical GM offering used.
My suggestion would be to use the 4.3 fuel injected drivetrain, a 10 bolt camaro rear axle with 3.08 gears, either a TH350 or a TH200-r4 tranny, and a IFS kit up front. The rear suspension can be leafs, 4-link with coil overs or even trailing arms and springs but again fabrication/modification are needed in all cases.
Have fun with it but make a plan.
