Okay... we're being honest in our opinions to help you sell, so here's my thoughts. There are some things pictured and described that may be working against you:
A buyer (unless they show up in person) can't tell the quality of a paint job but they can see how much attention to detail went into it. Your pics show overspray in many areas, hard lines and grommets under the bonnet that have been painted blue, etc. Rightly or wrongly these things may lead a potential buyer to conclude it was a 'fast & cheap' paint job done to sell the car. If I were selling this car I would clean up those areas and/or replace the grommets with new.
Your engine was professionally rebuilt. There are lots of different ideas on what 'rebuilt' means. Again, perhaps unfairly, your pictures and words do not indicate an engine that has been thoroughly rebuilt. Apart from the somewhat dirty look, the engine block is painted blue (and the oil pan red) rather than black. Not too hard to repaint in black by just working around the ancillaries. Hopefully the oil pan that was sealed with silicone is corrected and need not be mentioned again, but a thorough detailing of the engine will help 'sell' the quality of the rebuild.
Any details you can add to the story (who painted it, who rebuilt the engine) may improve the tale.
The interior is vary hard to get a look at in the pictures, especially the seats. If a buyer can't see something he will assume the worst.
Any small missing or incorrect parts are suggestive -- for example I would get a proper battery hold-down. Just my personal taste, but a set of correct air cleaners and an original style radiator cap may look better. Adding labels to the air cleaners and brake fluid reservoir is nickel & dime stuff but adds to the over-all effect you want -- that someone cared about this car.
The ground strap is missing or at least not where it is supposed to be, another cheap-to-fix (but correct) item. The hot lead from the battery to solenoid cable is much longer than needed, again -- just looks like someone grabbed whatever would work.
The heater pipe is missing on the ignition side of the block but I'm not sure that is a big deal. If you can get one cheap it will again 'add to the effect'.
You have a new wiring harness but I see those red wires running over to the right hand battery post. Not sure what that is but makes it look like it was cobbled together to make something work.
As noted, covering the dash with black vinyl might help and you should definitely show the windscreen in place. BTW - the car is more fun to drive with the aeroscreens but looks more normal I think with the windscreen. So, show both.
Well, this may have sounded pretty harsh but really you have an excellent car and it is a shame not to see it in the best possible light. If you have to spend a hundred bucks or so on some parts & materials and spend a couple of days under the bonnet removing paint and detailing with paint I think it could be worth thousands in the final tally.