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Typical click-bait youtube video with lots of wrong info, forever rambling, and no photos of contemporary Nascar motors. Yunick's car was running a 427 BBC and a de-stroked 427 BBC (416) during the heyday of the Hemi and Ford Big Blocks in Nascar. Small blocks did not become competitive until the mid 70's when Nascar started requiring restrictor plates. At that point, there was no contest between the power to weight ratio of a high-reving SBC and a heavy choked-down BBC. As a side note, last summer I was able to get an NOS in the box 1966 nascar style GM dealer accessory air cleaner for one of my Chevelles out of a 50-year collection filled with rare and NOS high performance parts. In that collection was a set of Smokey Yunick heads among a warehouse full of other unbelievable parts.
This is the biggest sack of bullsh*t I have seen for a long time!
Poor Smokey, he must be rolling over in his grave knowing that this is on the internet.
Does anyone else think that the video was AI generated? ( Always Incorrect )
Last edited by Charlie Jones; Jan 9, 2026 at 07:08 PM.
Typical click-bait youtube video with lots of wrong info, forever rambling, and no photos of contemporary Nascar motors. Yunick's car was running a 427 BBC and a de-stroked 427 BBC (416) during the heyday of the Hemi and Ford Big Blocks in Nascar. Small blocks did not become competitive until the mid 70's when Nascar started requiring restrictor plates. At that point, there was no contest between the power to weight ratio of a high-reving SBC and a heavy choked-down BBC. As a side note, last summer I was able to get an NOS in the box 1966 nascar style GM dealer accessory air cleaner for one of my Chevelles out of a 50-year collection filled with rare and NOS high performance parts. In that collection was a set of Smokey Yunick heads among a warehouse full of other unbelievable parts.
Very cool, whats the rest of the car look like? I've seen those come up once in a while for sale, usually very expensive.
For the uninformed, is that air cleaner drawing air from the (non-functional) heater box, or is the photo somehow misleading me? Obviously, cabin air via the heater box would be cooler than from the engine compartment, and therefore more "powerful."
For the uninformed, is that air cleaner drawing air from the (non-functional) heater box, or is the photo somehow misleading me? Obviously, cabin air via the heater box would be cooler than from the engine compartment, and therefore more "powerful."
Chevy Mystery Motor.. part 409 part Mark 2 design, did any of these engines ever race or just all experimental?
Five of them raced in the 1963 Daytona 500. One by Smokey Yunick, ( driven by Johnny Rutherford) Another by Junior Johnson, Which he still owns, mystery motor and all.
Can't remember who the other three were.+
After the 500, NASCAR deemed the "Mystery" motor Illegal because Chevy couldn't produce enough of them, to meet the standard of a "production" engine
In one of the early 1963 issues of Hot Rod Magazine There is a detailed article on the "Mystery" motor.
Last edited by Charlie Jones; Jan 10, 2026 at 11:01 AM.
The air cleaner is called a cowl plenum air cleaner. It draws air from the high pressure area at the base of the windshield. The same place that delivers air into the kick panels. GM first built them for the 2x4 409 Z11 impalas. There were 2 427 engine designs in 63. One was a larger displacement "W" motor found in the Z11 cars. The other is the MKII prototype Mystery Motor 427. It looks a little like a BBC, but all of the parts are specific to that motor. It was raced in nascar in 63.
The Chevelle my air cleaner is on is still a project. It started out as a 6-cylinder 3 on the tree, but now has a 427 with 4 speed.
The air cleaner is called a cowl plenum air cleaner. It draws air from the high pressure area at the base of the windshield. The same place that delivers air into the kick panels. GM first built them for the 2x4 409 Z11 impalas. There were 2 427 engine designs in 63. One was a larger displacement "W" motor found in the Z11 cars. The other is the MKII prototype Mystery Motor 427. It looks a little like a BBC, but all of the parts are specific to that motor. It was raced in nascar in 63.
The Chevelle my air cleaner is on is still a project. It started out as a 6-cylinder 3 on the tree, but now has a 427 with 4 speed.
Five of them raced in the 1963 Daytona 500. One by Smokey Yunick, ( driven by Johnny Rutherford) Another by Junior Johnson, Which he still owns, mystery motor and all.
Can't remember who the other three were.+
After the 500, NASCAR deemed the "Mystery" motor Illegal because Chevy couldn't produce enough of them, to meet the standard of a "production" engine
In one of the early 1963 issues of Hot Rod Magazine There is a detailed article on the "Mystery" motor.
Does Junior ever show his car anywhere? I would love to see it!!
The air cleaner is called a cowl plenum air cleaner. It draws air from the high pressure area at the base of the windshield. The same place that delivers air into the kick panels. GM first built them for the 2x4 409 Z11 impalas. There were 2 427 engine designs in 63. One was a larger displacement "W" motor found in the Z11 cars. The other is the MKII prototype Mystery Motor 427. It looks a little like a BBC, but all of the parts are specific to that motor. It was raced in nascar in 63.
The Chevelle my air cleaner is on is still a project. It started out as a 6-cylinder 3 on the tree, but now has a 427 with 4 speed.
It looks as though they stole an image of the underhood of your car for the video.
Isn't that image of the underhood previously posted your car?
Excellant!! Two of the very best ***-kicking legends! Somewhere there's a pic of Don with his arm around my neck and head against mine - smiling (me too!).
I have read many of his books & articles. He truly had the need for speed.
