I think it could run altered easily, ut it's possible with the rules for the Gas classes it could easily run Gas class too. Gas class rules limited altering the wheelbbase, and your's appears to be close to stock wheelbase. They also limited engine height to crank centerline of 24", so if your crank is not higher than 24" it would be OK for the Gas class. They allowed 10% engine setback, but obviously your engine is not setback at all, it's way forward, so I'd guess they would base the engine location as to how far the "firewall" is moved back. If your engine sits in there without too much firewall movement from where the original trunk wall was, then I think it could run the Gas class too.
At the end of the Gasser class era they were pretty loose with the rules, and a Corvair body on even a tube chassis could easily pass NHRA tech and run in the Gas class.