69 Dodge Dart GTS - Opinions
A couple more things to consider. Mopar people are very opinionated about Fender tags and or build sheets as well as if the car is numbers matching. You said your car is numbers matching (big plus) do you have the fender tag and or build sheet? In stock form a numbers matching 71 GTX will be worth more then a non-numbers matching 68 dart 340 GTS in comparable condition. So base car vs base car you 71 is ahead. and if the 68 GTS does not have a fender tag and or build sheet that's another hit.
The retro rod part is probably pretty close to the same money to do give or take especially since it looks like it's being done by the same shop (except engine). The mods done to the Dart for the most part could be changed back if a new owner wanted a more stock GTS look. any chance the original GTS motor is around? I think side by side all retrod out the GTX would be worth a bit more due to numbers matching engine and body style (thanks Fast & Furious) but people do get all excited when a real hemi is under the hood. in the picture I attached the front fenders look twisted....... maybe its just the picture.
The 440 in your car is worth more to your car then the value of a standard 68-70 440 since it's numbers matching. The Hemi in the Dart is worth about 25-30k plus depending on the parts that they used to build (new vs original) . Hemis are expensive to build and fix if needed remember that.
One thing you said is you really like your car and it sounds like you have put a lot of heart and soul into it. The dart is super cool and I don't doubt you will have a blast driving it and showing it off. But remember the shop will finish your 71 GTX and I am assuming it will be for sale at some point.
I am building a 68 Formula S 383 4-speed car that I am doing a slight resto rod with suspension upgrades and very original 69 charger 500 that will stay stock because of over all value. I have owned versions of both of the cars you are talking about so my likes are all over the board but I really love the A-bodys. I would love to own that 68 GTS or your 71 GTX for that mater but I would not trade the 71 gtx for the 68. How about take the GTX with you when you move and find a local shop to help you finish it. Hope you still have the 71 GTX rocker trim I saw in the fist pictures. Those are gold for 71 GTX people.
In the end if you go with the 68 Dart GTS ((((Awsume it's a cool car))))) if you keep the GTX I can't wait to see it when it's done.