So let's get this straight - you're asking us to evaluate an ad for a $2,500 beater that you could probably get for less if you waved cash in the guys' face then you want to put a GM drivetrain in it? Strange way to introduce yourself.
But OK, let's play along. That car looks pretty rust free which you confirm. If it was on the east coast it wouldn't last long so your perspective is slightly skewed because $2,500 is a good deal for that car. If I was still looking for a Dart, I'd snatch that up in a heartbeat and would probably be OK paying more for it including shipping it across the country since there does not appear to be any major surgery needed.
The guy is offering a big block setup pretty cheap that would fit without any fab work. Filled, stock block low deck strokers can push well over 700hp at the crank so you'd have to weigh that against whatever would be needed to put in a Brand X driveline. 20K for a low deck stroker would be kind of outrageous, I can't fathom it costing anywhere near that much. Hemi anything is ridiculously expensive, especially when you can make decent power with a wedge platform.
If you're making any sort of power, you essentially have two choices; Dana 60 or Ford 9". Clearly you don't care about brand loyalty so get the 9".
But seriously, why not just buy a Nova? All your stuff will fit without fabrication and you won't have to deal with all the dirty looks and people calling blasphemy for mixing brands. Putting a GM drivetrain in a 69 Dart is kinda like putting a kick me sign on your own back, you're inviting ridicule. Sure, some may like it and think it's cool but 99% of Mopar guys will hate it.
If you were at a level where you tried everything you could with a Mopar platform but couldn't keep up with the big dogs then OK. But to come here asking for opinions about something that most of us don't really take kindly to then say you don't want to hear any criticism about it? Good luck with that. What are you trying to prove? No one cares if it can be done.
