Basic /6 costs for upgrades to a 70 Dart

Hi,
I"m selling a 70 slant six that I just posted today and I have never restored a car before but would like to hear what a ball park cost would be to upgrade a low options swinger to the 340 version or to even another 8 cyl that would make the car a bit more fun (nothing too crazy). I'm talking rebuilt equip/ engine/trans/ and anything else you know it would need to make that transition. Also availability of these parts and if you'd go to a rebuilt as first choice. My budget is probably about 2k. Would I just be better off buying one that already has an 8 in it and selling my current 6 cyl?

I"ve learned alot in a short time from this website but I'm pretty new at this. But the longer I've had the car in the driveway the more it is growing on me although I'm not sure I'd want to keep it in it's current form.
Any help is appreciated.
thanks,
Jay

There are many here more expert, but since nobody yet answered, I'll answer from what I have read:
1. Motor mounts - Schumacher, etc. Have heard of a ~$100 set. Other option is to change the K-frame.
2. Transmission is different for V-8. At least $100 used.
3. The driveshaft may also change.
4. Most people change the 7.25" rear-end to 8.75", especially if racing. Then #3 for sure. Maybe $300.
5. If #4, most people change to the later bolt pattern (called BBP, 4.5" circle). Then you must change the front hubs to match or carry 2 spares. Set of 4 wheels & tires, $400+
6. With #5, most people install front disk brakes. $100 junkyard, $700 after-market.
7. V-8 requires a different steering link to clear the engine. $50+.

If you want a car to drive, consider upgrading the Slant Six. I would say people have as much fun and pride with that and will drive it more with teh better mileage. You could put in a turbo for maybe the same price, though you have to be a good welder or know one. To me, the attraction of the car hobby is being a little unique. How many times do you go to a car show and see rows of Camaros or Chevelles with a 350 and Edelbrock carb. All the engine bays look like clones. I like to see the cars where somebody had to think and design a solution.

Thanks, and an interesting perspective. Speaking of solutions, I had seen a twin turbo on here that took some real thinking.

X2 what Bill said and prices possibly be even more than he estimated. Even though I have EVERYTHING to convert my slant 65 Dart wagon over to a 340/904/8.75 rear end, I decided to do a slant in it - a matched and rebuilt set of triple SU carbs and intake, 6 into 2 headers, O/S Engnbldr valves/340 springs/shaved head, swap to a 4 speed, 3.23 equipped 8.75 with rear discs (hardware courtesy of one of our FABO members. Other than the head, I had all the other stuff. I had Leanna pretty-up the Lynx triple SU intake to match the Offy valve cover she did for me. No cookie cutter engine compartment here plus some extra power over a stock slant.