66 Big Block date code?

[William B.]

My 66 427 has a intake manifold that was cast one day before the car was built? Is that possible or was the manifold changed? I got the manifold date from the casting which is correct, but the web site for the corvette birthday, could it be off by a couple of days or is everything ok one day apart? Thanks for any responses.

[Jack H.]

Re: 66 Big Block date code?

Think about this one for a minute.... You've got a BB and the intake, block, and cylinder heads were cast in Tonawanda, NY. Then, the engine was built & tested in Tonawanda and shipped on to St. Louis for installation into the car.

Getting a large 'chunk' of engine from Tonawanda, NY to St. Louis, MO in ONE DAY is real trick! Casting dates of engine components need to preceed the engine's final assy (what's on the stamp pad) by 0-6 months. Then, the completed engine assy needs to pre-date the car's final assy date by 0-6 months.

But, you only get a vehicle final assy date by 'interpolation' (based on adjacent end-of-month Chevy production figures). If a given VIN happens to fall VERY close to an end-of-month number, the odds that the interpolation method is accurate are good. But, if the specific VIN falls toward the middle of a month, then things get muddy....

While some birthday calculators are pretty intelligent (know about strikes, know when Sat/Sunday fell and what GM recognized holidays were), they just aren't smart enough to comprehend line shut down episodes, wild cat labor interruptions, line speed up/slow down changes, authorized overtime, and third shift/swing shift additions. So, the crystal ball breaks down in computing a Corvette's birthday to a HIGH degree of accuracy....

Personally, I look at birthday calculations as being accurate, MAYBE, within a given week. And, I understand mid-month jobs tend to be less accurate than start of month/end of month builds.

[John H.]

Re: 66 Big Block date code?

What matters in this case is the relationship between the intake casting date and the engine assembly date stamped on the block pad, not the car's final assembly date. The intake MUST have a casting date prior to the engine's assembly date, as it was installed at Tonawanda and shipped as part of the engine assembly.

[William B.]

Thanks Everyone, I need a New Intake!! *NM*