No, it's far from original, too. The real '64 & '65 Coupes had 289 engines. There was one Coupe that was supposed to get a 390 motor, but never did.
This engine is based on a Ford 351 Windsor. It's a 392 Ford Motorsports crate motor. That means it's been bored .030" over for a 4.030" bore and stroked to 3.850" from 3.50", with forged pistons and forged steel connecting rods. The heads are Ford Racing GT40 aluminum cylinder heads. The camshaft is a hydraulic roller cam along with roller rockers, and a nominal lift of .570" lift and 236° duration at 0.050" lift. The fuel cell, electric fuel pump and regulator provide sufficient volume at 2.5 psi to feed those 48-IDA Webers. Spark is provided via an MSD ignition box, and shared among cylinders by a billet MSD distributor.
Four dual-throat 48-IDA Webers sit atop an aluminum intake manifold. On the downstream side, there's steel tube headers and four-into-two mufflers on each side, all coated in VHT white.
So now that you know "whutz in dere?", here's what comes out: Well, for starters, there's a genuine 435 HP on tap, along with roughly 500 lb. ft. of torque. Redline is set at 6,000 RPM, and it will pull all the way there (and over!).
All in all, a very nice monster Ford Motorsports small block...that acts like a big block!
...and here's a bit o' video to entice you, since you've come this far. Enjoy!