[ImperialCrown]

Welcome to Allpar. It was in 1988 and again in 1998 according to the Allpar article: http://www.allpar.com/trucks/b-vans.html
It doesn't mention how much the dimensions were changed.
Seat and instrument panel clearances to the doghouse were also changed.

 

[TWX]

Huh. I drove an '84 Royal 350 Maxiwagon and a '97 Ram Van 2500, and the doghouse covers were identical other than the color. If they moved the engine forward they didn't change the cover. I moved up to a '98 Ram Maxiwagon 3500, and it felt more like they moved the dash and seats rearward than moving the now-redesigned doghouse forward.

 

[flblessk]

I'm trying to find out what years had the best engine access from the interiour because its much easier and safer to work on from inside, especially during hard weather if you don't have a shop or driveway available. I've read the allpar article.

 

[TWX]

I pulled heads in a junkyard from a '90 or so, that was not very much fun. It's hard to get the exhaust manifolds off because of the body of the van being so close. Top-end work would probably be fairly easy, but nothing on the front or deep in would be accessible from inside. The A-series (flat front) vans would probably be fairly easy to work on, but those are an entirely different animal.

Full-sized vans just suck to work on.

 

[MoparNorm]

I pulled and rebuilt my 1972 360, it was surprisingly easy and top end work was easier than leaning over the fenders because you could knell right beside the engine.
Pull the passenger seat and the motor lifts up and out the passenger door.
Piece of cake, a one man job, but easier with two.