I am installing a 454/489 Big Block in my 1966 SS.
I am concerned with hood clearance using the standard SS hood.I have been looking for a low profile intake manifold that would work. Offenhauser makes one, but it is a 2X4 setup.

Anyone done this before?

Some of the early 70 big block Vettes had a low profile single four aluminum intake. Not sure of the part number

I have heard from 2 different sources that the Performer RPM will fit under the stock '66/'67 SS hood. Both actually had them on their '67's, so it's not just heresay. I'm planning on running one on my '67 SS with a Q-Jet and dropped base air cleaner.

Performer RPM will fit with a drop base air cleaner and a 3" element, but there is so little clearance that you cannot run any type of spacer, including the heat shield with all of it's gaskets. I'm not sure that the motor is getting adequate air flow because of this, but for added air flow, I am running a K & N top flow plate.

Mike

Everyone mentioned the Performer RPM, but what about the regular Performer? Its about 3/8" lower than the RPM...

As for the 2X4 intake, the Edelbrock C-66 2X4 (#5240?) also fits (I have that under my stock 1966 SS hood)...

The Weiand Stealth manifold w/Drop base, and 3" Element fits perfectly with room to spare.

I have a 66 Camino with a SS hood. I am currently using a Weiand stealth. I had to trim the base and and also bang the bottom of the air cleaner to get it to fit. But it fits. I am using one of those aluminum heat shields under the carb. I had to leave out a couple of gaskets to get it under there. There is only about 1/8" between the top and the hood. I worry about the air cleaner top being so close to the air horn. I'm also using Moroso solid mounts.
I might get one of those C-66 dual quad manifolds. Laterman--Josh

These cars could be had with the L78 engine and a drop base air cleaner. The L78 intake manifold is fairly tall. Something to compare to.

I am running a Edelbrock Perfromer Carb, Edelbrock Performer Manifold on my 396 in my 66 Malibu with a GM drop base air cleaner plus a Edelbrock Heat Sheild under the carb (.320 I believe) and some room to spare, not much. I had a Performer RPM installed but did not like the lack of clearance issue. Since I do not race it is not big deal to me. P.S. You can check out the spacer heat shield in my signature engine pic.
Jesse