(Image courtesy of Hot Rod)
The staff at Hot Rod magazine got the chance to dyno test a one-off Chevy 427 Mystery Motor built by the legendary Smokey Yunick in 1963. Although the 427 isn’t officially part of the Mark IV family, this Mark II engine is essentially the predecessor to the Rat motor, which came along in 1965. This experimental “Mystery Motor” was basically a modified version of Chevy’s W-series engine. It featured more conventional wedge-shaped combustion chambers and larger, canted valves compared to the original W-blocks. The top secret engine was used inside Junior Johnson’s Chevy at the Daytona 500 and was the forefather of the famous Rat motor.
Depending on who you ask, anywhere from 17 to 50 Mark II 427s were made. These engines are rare and highly historic–and Hot Rod got to open one up and then dyno test it. Click over to Hot Rod to get the details on the experience, including tons of photos and all-important dyno numbers.
Any guesses?
I was born a chevy boy in1968 and I will be a chevy boy til the day I die they have the most dependable engines
I love the big block torque!
I don’t think anyone would use a tiny carb like the one in the photo for a big block race engine.
In the day that could have been a 950 three barrel,they used them alot on the big tracks.With a holly ,outside look,s can fool you!~!
I remember my first 427 Chevy a .060 over 435hp one from 1966 with a 850cfm center pivot Holley from a NASCAR ford engine. The article should have had more info like rod bolt size and cam specs. It would have been nice to compare it to the 427 production engines. Not quite as fast as my Ford 427 but good for 11,s in a street car.
I worked alot on a high riser 67 farlaine 427, he had the parts to make it a low riser ,med,riser and high riser457,s detroit locker c6 or big shaft toploader.Back then it was the fastest car i had ever driven,that thing would wake you up in a hurry.My other buddy came back from Detroit with a 67 chevy 2 327 done,that little mouse killed the big block every time,changed drivers ,every excuse you could dream up.If it was a half mile race the ford may have got him but the ford used to run out of rpm,no lies
I own a 1957 corvette that ran a mark 2 mystery motor that came from smokey yunich. It was campaigned as an A/MP car in the early 60’s Boy I sure wish I had that motor in car now. Would be worth serious $$