Differences in 3885069 Intake Manifold

[R N.]

Hello All,

I'm wanting to learn more about the 3885069 intake manifold that is used on my '66 L-72 (March'66). Reading information at hand I've noticed some different configurations to this manifold.

I've seen 3-different configurations all where the carb mounts. One design is 2-small round holes with one larger one, another is both sides open with center divider and the last being all open with no divider.

My question is what is the correct design for my car? And what are the advantages or disavantages of these designs?

I thank you in advance of your help.

Best regards,
Kurt N.

[Mike M.]

Re: Differences in 3885069 Intake Manifold

first design you describe is an original, unmolested critter. last two designs you describe have been Bubba-modified. mike

[Duke W.]

Re: Differences in 3885069 Intake Manifold

Opening up the center divider turn the manifold into "sort of" a single plane type. This will increase top end power at the expense of low end torque, which makes sense for racing, but not for road use. This modification will also require carb rejetting to maintain an optimum mixture and fuel distribution.

An unmolested manifold is certainly best for a road engine.

Duke

[R N.]

Mike, Duke, thank-you.... *NM*

[Jody Balch]

Re: Mike, Duke, thank-you....

Kurt,

I have an original unmolested 069 intake dated 11/67 and it has two open ovals with a divider to the top of the plenum. I have read that this configuration was called the 2nd design and came out in late 1966 (maybe July). I have seen several others like mine with late date codes and they were identical, maybe the same "Bubba."

JB

[R N.]

Mike, Jody, more questions...

Don't have it in front of me, but I believe the book Corvette by the Numbers stated different designs as to what Jody is talking about.

Mike you said the first design I mentioned was correct for my car. Do you know if these later designs were ever done at the factory? You see very few of these early three hole bases.

Thanks,
Kurt

[Michael H.]

Re: Mike, Duke, thank-you....

Jody,

I believe you are correct. There was a 1st and second design on the plenum divider. One had two holes and an oval slot and the other had two ovals with a center divider. I'm not exactly sure when this design change occured but I believe it was during the 66 model year?