used high top fitment guide?

[surfmore72]

Im looking into adding a hightop to an extended van as part of a build out.  I am hoping to save money by removing a used top from a salvage yard.  I have neither van or hightop currently.   
Is there a simple guide to what model/year combos match up?  
Would it be possible to mate up a standard length hightop to extended van?  I have good mechanic and carpentry skills, "ok" fiberglassing skills ,and my good friend is a successful artistic welder and has offered his services 

I assume GMC/Chevy from same years but are there any subtle differences between years?
I am also very interested in late 90's fords (trying to avoid the spark plug issue...is this that big a deal?)
These vans all look alike...Any chance of cross platform and or different companies matching up or being close enough to "fudge" with some alu angle iron/fiberglass/silicone?

Im strapped for cash on this build but would love for the Mrs to be able to stand up (im 5'11" so ideally me too but if i cant find a 24"inch top ill settle for anything taller than stock).  Looking at touring country for 4-6 months to find a job and a new start with wife.  Cant wait to start a build thread (April is when we move FROM Hawaii TO the mainland)!

 

[Almost There]

The North American vans were unchanged for years - for example the GMC/Chev line started in 1961 and has had only 4 generations since then. Wikipedia is a great source for finding the generation information for each of the manufacturers.

I'm not totally positive but I think that the second and third generations were very much similar in roof length. Basically, that was when the hood got extended further forward as the engine was moved further to the front but the rear body stayed very much the same.

You can certainly put a shorter high top on the extended van, just set it back further on the roof. It leaves you with no high top over the drivers compartment and might look a little odd but if that's okay with you then who cares. The other choice is to cut it mid point and fiberglass in a new section...

Anything other that the 24" high top will not give either of you standing height so you do want to find one of those. I have a 6'2" standing height in my van and that's after putting in finished ceiling and flooring, either of which could have been made a little thinner if I needed more height.

When you get closer to having a van in the driveway and are ready to find the high top, I know some really knowledgeable van geeks who could help you zero in on the exact match in the high top. No point in doing that now because you don't know what van you'll end up with.