What's it worth now ?

Car looks terrific in the picture and straight. Things I think hurt a cars value race or not is

Non body color engine compartment
Cut out inner fenders
messy wires, hoses, ect

Stripped out interior, original dash and/or gauges missing
cheap plastic race seats, missing trim

Non body color trunk cut out spare tire well

All the above IMO will make a car worth much less money even if its a race car.

I bought a Demon with many of the items listed above for $11,000. About Eight years ago on ebay. Bad buy on my part but it was turn key fun when I didn't have any other running cars for drag racing. Today I believe that Demon would not sell for even half of what I paid for it and it is a real 340 car with build sheet and all, although with non matching numbers 340 engine.

I would say about $5000.00 +/- on your car