I also posted this in the Big Block Forum. The '66 L69 manifold I have has what appears to be a date code with numbers "151". What does that mean? Is it the 151st day of 1966? Manifold casting number is 393238. It also has a large "AZ" cast in the front edge and a large letter "F" on one of the runners.

 

Any '66 442 fans know how to decode casting date info for intake manifolds?

 

Hello,

The intake FAQ here basically confirms that you have what you say you have. The "393238" casting number and "F" ID code both coorespond to the L-69 manifold.

As to the date code: yes the code is a Julian date, which means it is the 151st day of the year. However it does not tell you which year. I'd also guess that it was 1966, so that means that it was May 31, 1966.

Tuesday, May 31.

Nice weather in Detroit that day. Mid 50's, partly cloudy. Not much breeze.

I don't know what the "AZ" means. I will leave that to the experts on this forum. The ones who actually work on the cars, and don't look up historical weather data just for kicks

 

Three revisions were used in production, AL, AU, and AZ. The first two have the small pad for the center carb that brought about a service guild bulletin to use Permatex #1 on the base gasket to help prevent vacuum leaks. AZ had the real fix, a bigger pad that supported the entire carb base. AL has a pedestal at the back for the coil; the others have a stub and bolt hole between #6 & 8 ports.

 

Thanks for the info, Run to Rund. I finally know what the letters mean and am glad I have the "good" manifold. Now, if I can find some '66 Olds engine paint in spray cans that's close to the original bronze or whatever they called it.

 

Fusick.com for the paint

 

I have to dissagree......... I have tried every paint available and NONE of them are correct. I have had the 65 442's since 66 and now have five of them. I've also parted out 15 of them and have untouched engines for comparison. Bill Hirsh used to have a perfect match in the early 90's, but since they took the lead out of the paint, it isn't even close. I sent it back and talked to him for an hour and he said the new formula must have caused the difference ????

 

One of the things I've found is that the heavy metallic in the engine paint makes it very susceptible to application technique. If you apply several light coats (as we've all been taught to do with spray paint) the color is too light. If you apply a single wet coat (as the factory did, runs and all) then the color looks darker and more correct. This effect is especially pronounced with the 455 blue.