[Zooguy]

Are the standard four-barrel intake manifolds interchangeable between the 389 and the 421 in 1966?

Did anybody make a dual quad intake that will go on my 1966 389?

[Kenth]

1966 326/389/421 4-barrel uses the same 9782896 intake manifold.

Afaik, Offenhauser and Edelbrock has made dual fourbarrel intake manifolds.

[61-63]

If you want your setup to resemble the early 60s factory super duty setups then get an offenhauser intake, which spaces the carbs as did the factory intakes. Edelbrock intakes jamb the carbs closely together and you can't use the '56/'57 Corvette air cleaners that the Pontiac SD setups used. All of this has been discussed on these forums many times now.

[Zooguy]

I didn't know if anybody made a high-rise or tunnel ram style which put the carburetors away up in the air.

[tom s]

We introduced a 2-4 tunnel ram last year on this site.Doubt it will fit under your hood without a scoop.It is a reproduction of the factory 421 Bathtub tunnel ram.Made 2 versions,one for early heads and one for late heads.Should be EZ for you to find the threads.Tom