In 1968, Baldwin-Motion rooted their business expertise to five cars. They dubbed them the “Fantastic Five”, all packing a 427ci V8, all wicked units meant to go out and brawl on the street. The Chevy II, Corvette, Camaro, Chevelle and big-body Biscayne could all come swinging for the fences. Under the direction of Joel Rosen, big-block Chevrolets were liberally applied to the entire Chevrolet lineup in defiance of the corporate order that nothing smaller than a full-size GM car could come with anything bigger than 400 cubic inches. This put a kink in the works for dealerships who easily saw the writing on the wall when it came to sales. The Biscayne didn’t fall into the 400 cubic inch rule as it was a big-boy car, but it wasn’t mean to be a hero, either. It was the bucks-down car, the basic Chevy, and Baldwin-Motion took full advantage of that in 1968. They built a 425-horse 427-powered Biscayne that they dubbed the “Street Racer Special”. Weighing in at 3,600 pounds and on street tires, a Street Racer Biscayne could click off a mid-13 quarter mile with just minor timing work. That’s hustling nowadays, nevermind fifty years ago. 
In 1966, performance was only just starting to kick up and the Biscayne wasn’t the sleeper hit it would be a few years later. Instead, this was the truly basic Chevy…two tail light lenses instead of three, poverty caps, minimal chrome and two vinyl-covered slabs for seats. You could still make one into a runner, but you had to know your way around an options sheet. Which always begs the question, “How would you have done it?” 
Here’s our answer: sleepy Sandalwood Tan paint, poverty caps, and nearly no chrome on a two-door post sedan starts off the build. A big-block must be underhood…here, this build has taken some liberties. The .030 over 454ci mill that is under the hood now wouldn’t exist, but the big-block look would be just right. A Muncie four-gear would be a requirement. Anybody who walked by wouldn’t see anything to give it away (at least, once the add-on tach and three-port gauge pack disappeared). But slide onto that seat, fire off the mill, select first and stomp on the pedal as if you were trying to kick it through the floor. You’ll see what Rosen saw when he toyed with the COPO ordering process for his Street Racer Special Biscaynes. Minimal frills and maximum performance always wins.
That is cooler than the wagon. I likey.
When I was in high school (the 70’s) I knew of a Biscayne with a 396-badged big block. The only visual hints at performance were the headers. Orange valve covers, complete with 396 stickers, Edelbrock C-454 intake, big Holley hiding under a 454 truck air cleaner housing with a small lid on top of the big filter, and a relatively mild juice cam built the deception. The engine was actually a tall-deck truck block punched to 540+ inches. BIG for those days. He had a T400 and relatively modest gears. Pretty much anybody could put a couple of fenders on him in low gear, but he’d get a big bark out of the tires when it shifted into second, and just march on by.
He was crafty enough that he even blended the intake manifold spacers, plus painted the intake Chevy orange. This car was the true definition of a sleeper, and was probably a high-12 car, on L70-15 rubber, when high 12’s was rockin’. On slicks, with 4.56’s and a good converter, it was probably capable of laying down a high 11.
Back about 1980 one of the killer cars in stock eliminator was a black B Stock Stick impala, 1968 427 just like this….If I recall it was run by a guy that I think was named Bobby Blankenship. Big barge would pull the front wheels at least 9 \” in stock eliminator. Very quick car and amazing considering how big it was.
Prior to reading the description, I thought , maybe hoped, it would have had an 8.1 with a six speed but just as subtle as it appears on the exterior. .02