1966 IK engine code

[Edward M.]

I have a friend with a 1966 427 big tank coupe. The car was build in February of 1966, and has an M22 transmission with a VIN derivative that matches the car, and appears to be correct. The car has a 427 engine with an "IK" engine code.

Over the years various statements have been made regarding the IK engine code. The most frequent one that I hear is that the IK engine code was for a 1966 427 with a M22 transmission. Apparently there was some difference in the clutch setup with an M22, and this justified a separate engine code. Also apparently this engine / transmission combination used a different starter as well.

I think NCRS states that IK is the engine code for a 1966 427 with a M22 transmission.

I flat out do not know, and I am wondering if any of the 15 M22 equipped 1966 Corvettes have come to light, and more important, if they still have their original drive trains.

I did read one "interesting" comment to the effect that the "IK" code was supposed to be designated for an iron head 1966 L88, but that this option was deleted before introduction of the 1966 lineup.

Anyway, any insight / knowledge / rumors you could provide on this topic would be greatly appreciated.

[Rick A.]

Re: 1966 IK engine code

Ed - you resurrected that question back 0n 6/12 - not happy with the answers then?

[Joe L.]

Re: 1966 IK engine code

I have a friend with a 1966 427 big tank coupe. The car was build in February of 1966, and has an M22 transmission with a VIN derivative that matches the car, and appears to be correct. The car has a 427 engine with an "IK" engine code.

Over the years various statements have been made regarding the IK engine code. The most frequent one that I hear is that the IK engine code was for a 1966 427 with a M22 transmission. Apparently there was some difference in the clutch setup with an M22, and this justified a separate engine code. Also apparently this engine / transmission combination used a different starter as well.

I think NCRS states that IK is the engine code for a 1966 427 with a M22 transmission.

I flat out do not know, and I am wondering if any of the 15 M22 equipped 1966 Corvettes have come to light, and more important, if they still have their original drive trains.

I did read one "interesting" comment to the effect that the "IK" code was supposed to be designated for an iron head 1966 L88, but that this option was deleted before introduction of the 1966 lineup.

Anyway, any insight / knowledge / rumors you could provide on this topic would be greatly appreciated.

Ed------


There's no way that the "IK" code could have designated an engine for an M-22 transmission. That's because the transmissions were not part of the engine assembly. It could have denoted an engine INTENDED for later combination with an M-22. That may seem a bit like saying the same thing but it's not the same. An engine intended for an M-22 could just as easily have had any other Muncie variant installed.

The "IK" could have denoted an engine with a 12-3/4" flywheel, 10-3/8" clutch and 3859403 bellhousing. But, it's possible that was not the only difference from the seemingly same engine with a 14" flywheel. There's no way of knowing.

I'll offer this speculation, though: as most know, the 1965 L-78 engine used a 12-3/4" flywheel, 10-3/8" clutch, and associated bellhousings. I believe that early-on it was Chevrolet's intention to use the same set-up on, at least, 1966 L-72's. If that ever actually occurred I think it was only done at the very beginning of the model year. If so, the "IK" engine was simply a code used in early 1966 L-72 PRODUCTION regardless of whether the installed transmission was either an M-21 or M-22.

[Gene M.]

Re: 1966 IK engine code

Ed------


There's no way that the "IK" code could have designated an engine for an M-22 transmission. That's because the transmissions were not part of the engine assembly. It could have denoted an engine INTENDED for later combination with an M-22. That may seem a bit like saying the same thing but it's not the same. An engine intended for an M-22 could just as easily have had any other Muncie variant installed.

The "IK" could have denoted an engine with a 12-3/4" flywheel, 10-3/8" clutch and 3859403 bellhousing. But, it's possible that was not the only difference from the seemingly same engine with a 14" flywheel. There's no way of knowing.

I'll offer this speculation, though: as most know, the 1965 L-78 engine used a 12-3/4" flywheel, 10-3/8" clutch, and associated bellhousings. I believe that early-on it was Chevrolet's intention to use the same set-up on, at least, 1966 L-72's. If that ever actually occurred I think it was only done at the very beginning of the model year. If so, the "IK" engine was simply a code used in early 1966 L-72 PRODUCTION regardless of whether the installed transmission was either an M-21 or M-22.

Joe, Your explanation sounds the most realistic. I could see how the “IK” was the same clutch, flywheel, bell housing at the engine plant reflecting the same build as the ‘65 396 engine option but on an early ‘66 427. Being the design was changed as we all know and you pointed out.

It is so typical reading these post where someone wants their car to be something special.

[Edward M.]

Re: 1966 IK engine code

And I am still wondering if any of the 15 M22 equipped 1966 Corvettes have come to light? And what engine was attached to that M22?
Is is still a puzzle.

[Michael J.]

Re: 1966 IK engine code

According to my tanker information, 4 '66 tankers were equipped with M22s. All but one were L72s, one was an L36.

[Tom D.]

Re: 1966 IK engine code

I have often wondered if any of the 1966 M22 cars got transmissions "left over" from April of 1965. I know this is not likely.

On a more serious note, I'm asking Edward if the IK engine car has a protect-o-plate with a trans date on it?
What is the "P date" code on the Muncie?

[Edward M.]

Re: 1966 IK engine code

No protecto-o-plate with the car, and I do not know the date of the trans.

[James G.]

Re: 1966 IK engine code

Was one an early Roger Penske car? Dark Blue Coupe?

I remember seeing a white and purple Roadster with a Gold crest/coat of arms on the side purported to be factory with J56 and M22, race car from new for a West Coast Chev dealer... could be Alan Green but I am thinking another dealer.- .